Fingerprint registering method and fingerprint checking device

ABSTRACT

The present invention can achieve the reliability and simplicity in registering a fingerprint by indicating the quality of a fingerprint image by the number of pseudo minutiae, improve the security of an entrance/exit control system to register a fingerprint, detect the direction of ridge lines of a fingerprint accurately as much as possible, improve the security in checking a fingerprint remarkably, collect renewed registered fingerprint data by a host device and hold the registered fingerprint data of each gate as the latest fingerprint data, improve the operability by enabling to use identification numbers having the less number of digits, and register a fingerprint having a high match rate by automatically applying spatial filtering in re-registering only. A fingerprint registering method according to the present invention detects normal minutiae and pseudo minutiae in a fingerprint pictured by a fingerprint image pickup unit, counts pseudo minutiae in registering windows with normal minutiae at almost the center, determines the average number of pseudo minutiae in registering windows from a total of pseudo minutiae in all registering windows, and registers a fingerprint when the average number of pseudo minutiae is equal to or below a threshold.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a fingerprint registering methodfor registering a fingerprint by judging whether or not it has beenregistered and to a fingerprint checking device.

[0003] The present invention relates to a fingerprint registering methodwith security improved and to a fingerprint checking entrance/exitcontrol system.

[0004] The present invention relates to a fingerprint checking methodfor extracting a fingerprint in the direction of ridge lines inregistering and checking the fingerprint.

[0005] The present invention relates to a fingerprint checking methodfor checking a registered fingerprint and an affixed fingerprint toauthenticate personal identification.

[0006] The present invention relates to a fingerprint checkingentrance/exit control system for checking an affixed fingerprint and aregistered fingerprint to control the permission or not of entrance.

[0007] The present invention relates to a fingerprint checking devicefor checking a registered fingerprint and an affixed fingerprint.

[0008] The present invention relates to a fingerprint registering methodfor a fingerprint checking device.

[0009] 2. Prior Art

[0010] Fingerprint checking devices which check a registered fingerprintwith an affixed fingerprint to authenticate personal identification havebeen put into practical use. And, the fingerprint checking devices aredesired to easily register fingerprints with reliability.

[0011] As shown in FIG. 30, a conventional way of registeringfingerprints judges whether or not fingerprinting for a fingerprintimage pickup is for the first time (D1), if it is its first time,temporarily registers it (D2), if not its first time, judges whether ornot it is the second time (D3), if it is its second time offingerprinting, checks the temporarily registered fingerprint with thesecond affixed fingerprint (D4), judges whether or not they match (D5),if they match, formally registers (D6), and terminates normally. And, ifthey do not match, it is concluded as registration failure. In thiscase, registration processing can be repeated on another finger.

[0012] After binarizing a fingerprint shown in FIG. 31(A), it isthinning-processed as shown in (B), and a registering window in a squareframe is enlarged as shown in (C). In (C), N indicates a normal minutia,and P1 to P4 indicate pseudo minutiae. For example, a bifurcation pointhaving a bifurcation length of a prescribed length of a ridge line andan ending point having a space of a prescribed length or more aredetermined as normal minutia, and a bifurcation point and an endingpoint under other conditions are determined as pseudo minutia.

[0013] In the above-described temporary registering and formalregistering, registering windows each consisting of, for example, 36×30picture elements with normal minutia N at almost the center is selectedin the number of about 15 for example from a single fingerprint imageand registered as shown in FIG. 31(C).

[0014] Since fingerprints do not change, they are suitable forauthenticating personal identification. And, a registered fingerprintand an affixed fingerprint are checked by a fingerprint checking device,and when they match, the pertinent fingerprint is judged as of aregistered person. But, the fingerprint image pictured by a fingerprintimage pickup unit changes largely depending on chaps, wrinkles, dirt anda fingerprinting pressure of a finger tip. Therefore, checkingimmediately after the temporary registering mostly results in matching,but there is a disadvantage that a matching rate is lowered sharply witha lapse of time.

[0015]FIG. 32 and FIG. 33 are explanatory diagrams of fingerprint imagesand thinning-processed images. (A) in the respective drawings showspictured fingerprint images, and (B) shows images obtained by binarizingand thinning processing, and rectangles indicate registering windows. InFIG. 32, the fingerprint image is relatively good, and normal minutiaeare easily extracted as shown in (B). But, in FIG. 33, the fingerprinthas chaps and many pseudo minutiae as shown in (B), so that it is noteasy to select registering windows.

[0016] The fingerprint shown in FIG. 33 is formally registered becauseit has a high possibility of matching when it is checked with aregistered fingerprint immediately after the temporary registering. But,the states of chaps and wrinkles change with a lapse of time, and amatch rate is sharply lowered accordingly. To avoid it, it is desirableto obtain a fingerprint image with good image quality as shown in FIG.32, but it is hard to judge whether or not the fingerprint image is goodat the time of registering a fingerprint excepting when the fingerprintimage is heavily deteriorated such that mismatching results. Therefore,even when another finger is used to register a fingerprint in case ofmismatching, it is impossible to judge which finger is best.

[0017] On the other hand, there is a known fingerprint checkingentrance/exit control system which authenticates personal identificationby fingerprint checking to allow the entrance or exit. It is demanded toimprove the security of fingerprint registration in such a system.

[0018]FIG. 34 is an explanatory diagram of a system, in which referencenumeral 261 denotes a fingerprint registering device, 262 a fingerprintchecking unit consisting of a host computer, 263 a modem, 264 a privatebranch exchange (PBX), 265-1 to 265-n rooms such as an office, acomputer room and a vault, 266-1 to 266-n fingerprint checking gates,and 267-1 to 267-n electric locks.

[0019] The electric locks 267-1 to 267-n are for unlocking the doors tothe rooms 265-1 to 265-n, and the fingerprint checking gates 266-1 to266-n are provided to correspond to the rooms 265-1 to 265-n andconnected to the fingerprint checking unit through the private branchexchange 264. And, in a case of a small-scale fingerprint checkingentrance/exit control system, the private branch exchange 264 and themodem 263 may be omitted, and the fingerprint checking gates 266-1 to266-n and the fingerprint checking unit 262 can be connected by an LANor the like.

[0020] The fingerprint checking gates 266-1 to 266-n each have afingerprinting part, and read the affixed fingerprint to transfer to thefingerprint checking unit 262. The fingerprint checking unit 262 checksthe fingers registered in the fingerprint registering device 261 withthe transferred fingerprint, and transfers the checked result to thefingerprint checking gates through the private branch exchange 264.Otherwise, the fingerprint data registered in the fingerprintregistering device 261 is transferred to the fingerprint checking gates266-1 to 266-n to store in a storage device (not shown), a fingerprintchecking unit similar to the fingerprint checking unit 262 is providedat the respective fingerprint checking gates 266-1 to 266-n, and theregistered fingerprints can be checked with the affixed fingerprint atthe respective fingerprint checking gates 266-1 to 266-n.

[0021] And, when the registered fingerprint matches with the affixedfingerprint, the fingerprint checking gate unlocks the electric lock toallow entrance, but when they do not match, the electric lock is notunlocked to prohibit the entrance. And, when the use of a computer isallowed by fingerprint checking, the computer can be used when theregistered fingerprint matches with the affixed fingerprint and theelectric lock is unlocked.

[0022] Therefore, a person who has registered his or her fingerprint canenter a room or use a computer without using an ordinary key whenpersonal identification is authenticated by fingerprint checking. Insuch a case, by registering a fingerprint and a room as a pair, onlyspecified persons are allowed to enter a specified room. And, it ispossible to register a specified person to enter every room.

[0023] By registering the fingerprints of persons allowed to enter aroom in the fingerprint registering device 261, only fingerprintregistered persons can enter the room. To register a fingerprint, it isoften that registering is permitted according to a password, orregistering is allowed by using a registering key.

[0024] But, it is highly possible that a password is used by stealthunless its number of digits is increased, but when the number of digitsis increased, it is troublesome to enter the password. And, in the caseof using the registering key, there is a disadvantage that any personcan register his or her fingerprint by using the registering key.Accordingly, the security of entrance to or exit from a room afterregistering a fingerprint can be retained fully, but the security at thetime of registering a fingerprint is not sufficient. And, fingerprintchecking to authenticate personal identification is to check an affixedfingerprint with a previously registered fingerprint, and it isgenerally configured that to register a fingerprint, minutiae of afingerprint image obtained by picturing an affixed fingerprint areextracted as registered fingerprint data, the registered fingerprintdata is stored in a file, and the affixed fingerprint image is binarizedat the time of fingerprint checking and checked with the registeredfingerprint data read from the file. To extract the minutiae, thefingerprint image is required to accurately show the ridge lines of thefingerprint, and various types of image processing methods have beenproposed.

[0025]FIG. 35 is an explanatory view of a fingerprint checking device,in which reference 311 denotes a fingerprint image pickup unit, 312 amultivalued image capturing unit, 313 a fingerprinting judging unit, 314a ridge line direction detecting unit, 315 a spatial filter, 316 abinarizing unit, 317 a minutia extracting unit, 318 a registering unit,and 319 a checking unit. The fingerprint image pickup unit 311 takes apicture of an affixed fingerprint by a CCD camera, the multivalued imagecapturing unit 312 converts an analog image into a multivalued digitalimage and stores in an image memory (not shown), and the fingerprintingjudging unit 313 judges whether or not a fingerprint has been affixedbased on the multivalued image.

[0026] At the time of registering a fingerprint, the fingerprint isaffixed and pictured by the fingerprint image pickup unit 311, andcaptured as a multivalued image by the multivalued image capturing unit312. Based on the multivalued image, it is judged by the fingerprintingjudging unit 313 whether fingerprinting has been made or not, and whenit is judged as fingerprinting, the multivalued image is binarized bythe ridge line direction detecting unit 314. For example, with 16×16picture elements as one block, division into respective blocks is made,the ridge line direction is detected for each block, and conversion intothe multivalued image is made by the spatial filter 315. The spatialfilter 315 determines a luminance average value of focused pictureelements and multiple picture elements in the ridge line direction on amultivalued image captured by the multivalued image capturing unit 312,for example, and processing of determining the luminance of the focusedpicture element can be made with respect to the blocks.

[0027] The multivalued image processed by the spatial filter 315 isbinarized in the binarizing unit 316, and based on the binarized image,minutiae such as bifurcation points of ridge lines are extracted in aprescribed number by the minutia extracting unit, and data containingthe minutiae is stored as registered fingerprint data in the registeringunit 318.

[0028] In checking a fingerprint, the fingerprint is affixed andpictured by the fingerprint image pickup unit 311, and captured as amultivalued image by the multivalued image capturing unit 312. Based onthe multivalued image, it is judged by the fingerprinting judging unit313 whether fingerprinting has been made or not, and when it is judgedas fingerprinting, the multivalued image is binarized by the binarizingunit 316, the binarized image of fingerprint is checked with theregistered fingerprint data read from the registering unit 318 by thechecking unit 319, and a checked result output signal on matching ormismatching is sent to an unillustrated gate having an electric lock.

[0029]FIG. 36 is an explanatory diagram of dividing a pictured imageinto blocks, and when 512×512 picture elements are determined as onescreen, division into 1024 blocks is made with 16×16 picture elements asone block, for example. And, P_(1.1)˜P_(1.256) denote the pictureelements in the top left block, and P._(1024.1)˜P_(1024.256) denote thepicture elements in the right bottom.

[0030]FIG. 37 is an explanatory diagram of judging the direction ofpicture elements. In the ridge line direction detecting unit 314 shownin FIG. 35, using a 3×3 picture element direction detecting mask and apattern with its center as the focused picture element, the directionsof the focused picture elements are determined as shown in D1 to D8. Forexample, pattern 1-1 and pattern 1-2 are judged as the same horizontaldirection D1, and pattern 3-1 and pattern 3-2 are judged as the same45-degree direction D3. And, if not belonging to 16 types of directiondetecting mask patterns shown in FIG. 37, the direction of focusedpicture elements does not belong to any pattern. Therefore, the focusedpicture elements can be judged to belong to which of the eightdirections D1 to D8 in this case, they will be one of eight directionsindicated by 1 to 8 at right bottom of the drawing. And, each block isdetermined to have a direction that the number of picture elements inevery direction in the block is maximum as the ridge line direction ofthe pertinent block.

[0031]FIG. 38 is a flowchart of a conventional example, in which a blocknumber is initialized with m=1 (B-1). In other words, number m for 1 to1024 is allocated with respect to 1024 blocks in the image shown in FIG.36, and the block number m is determined as 1 for initialization. Then,with n=1 (B2), the picture element number n in the block is initialized.In other words, the number n for 256 picture elements in the image shownin FIG. 36 is allocated, and this picture element number n is determinedas 1 for initialization.

[0032] Then, contents V1 to V8 of a totaling register for totaling thenumber of picture elements corresponding to respective directions 1 to 8shown at the lower right of FIG. 37 are cleared to zero and initialized(B3). And, the direction of picture element P_(m.n) (m=1˜1024, n=1˜256)is detected by using a direction detecting mask as described inconnection with FIG. 37, +1 is added to Vx (x=1˜8) corresponding to amatched direction (B4). And, it is judged whether or not n=256 (B5), andif n is not equal to 256, it is determined as n=n+1 (B6), thenprocessing goes to step (B4). The above-described steps (B2) to (B6)correspond to histogram generation processing according to the directionin the block.

[0033] When n=256, processing on one block is completed, and it isdetermined as i=1 (B7), register No. i according to the direction isinitialized, it is determined as Sm=0 (B8), and a direction componentmaximum value Sm is initialized. And, totaling register Vi and themaximum value Sm are compared to judge whether Sm<Vi (B9), and whenSm<Vi, it is determined as Sm=Vi (B10), and Dm=i (B11). In other words,the totaling register Vi is determined as the maximum value Sm, anddirection No. i of the totaling register Vi is determined as directionNo. Dm of the maximum value Sm.

[0034] When Sm is not smaller than Vi, or after step (B11), it is judgedwhether or not i=8 (B12). In other words, it is judged whether or notprocessing has been made on eight directions, and when i is not equal to8, it is determined as i=i+1 (B14), and processing goes to step (B5).And, when i=8, it is judged whether or not m=1024 (B13). Namely, it isjudged whether or not processing on all blocks has been completed, andif not completed, it is determined as m=m+1 (B15). And, block No. m isdetermined as an increment, and processing goes to step (B2). Therefore,at the end of processing, the maximum value Sm of the directioncomponent of respective blocks is stored in a direction componentmaximum value storage register corresponding to block Nos. 1 to 1024,and direction No. Dm is stored in a direction storage registercorresponding to block Nos. 1 to 1024.

[0035]FIG. 39 and FIG. 40 are explanatory diagrams of detecting a ridgeline direction in a conventional example. In FIG. 39, (A) shows aschematic view of a multivalued image of a pictured fingerprint, and (B)shows a schematic view of a binarized image obtained by binarizing themultivalued image. Based on the binarized image, detection in the ridgeline direction on each block described above results in (C). Based onthe result detected in the ridge line direction of each block, themultivalued image shown in (A) is subject to the above-described spatialfiltering, and the result is shown in FIG. 40(D). It is apparent bycomparing the multivalued image of (D) and the multivalued image of FIG.39(A) that chapped portions are connected. Therefore, when themultivalued image of (D) is binarized, it is changed as shown in (E).When the binarized image of (E) is compared with the binarized image ofFIG. 39(B), it is apparent that the binarized image of (E) is clear.

[0036] In detecting the direction of ridge lines of a fingerprint in theconventional example, the direction of each picture element in the blockis detected, the number of picture elements corresponding to thedirection in the block is determined, and the direction that the numberof picture elements becomes maximum is determined as the ridge linedirection in the block. And, as to the directions that the number ofpicture elements is same, one of them is selected. Therefore, when thenumber of picture elements is same in directions which are intersectingat right angles and one of them is selected, there is a disadvantage ofhaving a possibility that the direction becomes opposite from the flowof the ridge lines. In other words, there is a disadvantage that theridge line direction not complying with the flow of the ridge lines ofthe peripheral blocks is detected.

[0037] For example, as shown in FIG. 41(A), in the ridge line directionpattern of each block, when a ridge line direction not complying withthe flow of the ridge lines of the peripheral blocks is obtained like ablock indicated by 321, it is changed by the spatial filtering to amultivalued image which is schematically shown in (B), then it isconverted into a binarized image which is schematically shown in (C),and a bridge is produced between the ridge lines at a portion indicatedby 322 which corresponds to the block 321. Therefore, there is adisadvantage that an error occurs when minutiae are extracted.

[0038] And, a system has been put into practical use which checks aregistered fingerprint with an affixed fingerprint, and if they match,unlocks a door to allow the entrance or allows to operate equipment. Bychecking fingerprints, security can be improved as compared with the useof a physical key. In such a case, it is necessary to manage theregistered fingerprints with reliability and to prevent misuse such asalteration of the registered fingerprints.

[0039]FIG. 42 is an explanatory diagram of a fingerprint checkingsystem, in which reference numeral 411 denotes a fingerprint checkingdevice, 412 a fingerprint reading unit, 413 a control unit, 414 astorage unit for storing registered fingerprint data, 420 a hostcomputer, 421 a processor (CPU), 422 a bus, 423 a random access memory(RAM), 424 a read-only memory (ROM) for storing data or the like, 425 ahard disk drive (HDD) for storing a large volume of registeredfingerprint data, 425 a registered fingerprint data, 425 b a datadestruction checking code, 426 and 427 an interface (IF), 430 a cardreader, and 431 an IC card for keeping registered fingerprint data.

[0040] The host computer 420 can be a personal computer, and the harddisk drive 425, which is now relatively inexpensive and small, has alarge capacity and can store a large volume of fingerprint data. Thestorage unit 414 in the fingerprint checking device 411 is aprogrammable read-only memory (EEPROM, flash memory, etc.) and can storeregistered fingerprint data for scores of people or several hundredpeople. And, if necessary, the registered fingerprint data stored in thehard disk device 425 in the host computer 420 can be downloaded to thestorage unit 414.

[0041] To check fingerprints in the fingerprint checking device 411, anidentification number (ID) is entered. To enter the identificationnumber, a keyboard or a ten-key which is not illustrated can be used, ora medium such as an ID card which stores an identification number (ID)can be used. And, registered fingerprint data corresponding to theidentification number is read from the storage unit 414, the registeredfingerprint data is compared with the fingerprint data of an affixedfingerprint read by the fingerprint reading unit 412 by the control unit413, and if they match, control of unlocking or the like is madeaccording to an output signal from the control unit 413.

[0042] It is also possible to store the registered fingerprint data inthe IC card 431. By reading the IC card 431 by the card reader 430, theregistered fingerprint data can be transferred to the fingerprintchecking device 411 through the host computer 420 and checked with dataof an affixed fingerprint. The registered fingerprint data is configuredby taking a picture of the affixed fingerprint, binarizing it,extracting a plurality of minutiae such as bifurcation points owing tothe ridge lines of the fingerprint, determining each minutia as made ofmultiple picture elements, and using binarized data rows of therespective minutiae.

[0043] To check that data in a file having the registered fingerprintdata is not destroyed, the data destruction checking code 425 b is addedto the registered fingerprint data 425 a. By this data destructionchecking code 425 b, a total value, exclusive-OR or scrambled value ofgenerating polynominal is used for all data contained in the file, andif the data stored in the file is changed even by one bit, this one bitchange can be detected based on the data destruction checking code 425b. But, if the contents of the file are totally exchanged, detectioncannot be made.

[0044] As shown in FIG. 42, the registered fingerprint data is stored inthe storage unit 414 of the fingerprint checking device 411, stored inthe hard disk drive 425 in the host computer 420 connected to thefingerprint checking device 411, or stored in a medium such as the ICcard 431 or an optical card using a magneto-optical record medium.

[0045] Where the registered fingerprint data is stored in thefingerprint checking device 411, and if it is exchanged with anotherfingerprint checking device having other fingerprints stored accordingto the identification number identical to the identification number (ID)stored in the formal fingerprint checking device, all operation on thesystem side is not different, the registered fingerprint data isexchanged, and if another fingerprint is affixed using the sameidentification number (ID) as before, checking results in matching.

[0046] Where the fingerprint data is stored in the hard disk derive 425in the host computer 420, the data file in the hard disk drive cangenerally be operated freely. For example, the registered fingerprintdata file can be replaced by another file having different data with thesame file name. Therefore, if some person who is not formally registeredattempts to register his or her fingerprint in another system and theregistered fingerprint data is reloaded by such registered fingerprintdata, a person who is not formally registered can use the systemillegally.

[0047] Where the registered fingerprint data is stored in a portablemedium such as an IC card or optical card, the registered fingerprintdata can be reloaded, so that misuse can be made in the same way asdescribed above.

[0048] Accordingly, it is thought to insert a key number with respect torespective registered fingerprint data. The key number is inserted at agiven byte of the registered fingerprint data, the byte number and thekey number are made confidential, and the key number is stored so thatthe formally registered persons are not revealed. Even if the registeredfingerprint data is exchanged, misuse cannot be made because the keynumbers of the formally registered persons are also changed. But, asshown in FIG. 43, if the same key number is used to repeatedly registerfingerprints, registered fingerprint data A, B and C become differentowing to the positional change of minutiae and change of data rows ofminutiae.

[0049] Accordingly, when registered fingerprint data A, B and C are readfrom the registered fingerprint data storage file and checked, the keynumber at the x-th byte from the leading address of respectiveregistered fingerprint data A, B and C matches, and other areas do notmatch because they have a random property. In other words, it can beidentified that the x-th byte where matching is obtained is where thekey number is inserted. Thus, the key number can be read from theregistered fingerprint data of the formally registered persons, so thatmisuse can be made.

[0050] And, a fingerprint checking entrance/exit control system has beenproposed to authenticate personal identification by checkingfingerprints, thereby allowing the entrance to a predetermined room orthe like. And, such a fingerprint checking entrance/exit control systemis desired to have an improved fingerprint checking accuracy.

[0051]FIG. 44 is an explanatory diagram of a fingerprint checkingentrance/exit control system, in which a host device 531, a plurality ofgates 532-1 to 532-n, and a given number of fingerprint registeringdevices 537-1 to 537-m are connected by a line 533 of a local areanetwork (LAN), the respective gates 532-1 to 532-n have fingerprintchecking units 540-1 to 540-n and electric locks 541-1 to 541-n, anaffixed fingerprint is checked with the registered fingerprints in thefingerprint checking unit, and when personal identification isauthenticated, an unlocking signal is given to the electric lock torelease it. And, reference numeral 534 denotes a fingerprint registeringunit, 535 a control unit, 536 a printer for outputting a list ofregistered persons, a list of setting or the like, 538-1 to 538-mcontrol units, and 539-1 to 539-m fingerprint registering units.

[0052] To register a fingerprint by the fingerprint registering units534, 539-1 to 539-m, personal information containing entrance allowinginformation such as name, identification number, post and room number inwhich he or she wants to enter is entered. The personal information andregistered fingerprint data are stored in a file (not shown) in the hostdevice 531. And, the personal information and registered fingerprintdata are downloaded to the gate in conformity with the entrance allowinginformation. In this case, desired registered fingerprint data can bedownloaded according to the demand from the gate.

[0053] When personal identification is authenticated by checking theregistered fingerprint data with the affixed fingerprint, it is knownthat the registered fingerprint data is renewed by the affixedfingerprint data, and the registered fingerprint data is controlled asif it is obtained by the latest fingerprint registering operation. And,it is known that when first and second registered fingerprint data arestored, the affixed fingerprint is checked with the first registeredfingerprint data and personal identification cannot be authenticated,the affixed fingerprint is checked with the second registeredfingerprint data, and if personal identification cannot be authenticatedyet, it is determined as a mismatch; but if personal identification canbe authenticated, the second registered fingerprint data is renewed bythe affixed fingerprint data (e.g., Japanese Patent Laid-OpenPublication No. Sho 63-301376). By such a method, the probability ofauthenticating personal identification by the second fingerprintchecking is improved, and the registered fingerprint data is renewedwhen the personal identification is authenticated, so that the latestregistered fingerprint data can be used to check fingerprints.

[0054] As described above, the fingerprint checking entrance/exitcontrol system is generally provided with the fingerprint checking units540-1 to 540-n in the respective gates 532-1 to 532-n to check thefingerprints in a distributed manner. Therefore, when theabove-described registered fingerprint data is renewed at the respectivegates 532-1 to 532-n, the registered fingerprint data at the gate with ahigh frequency of use becomes the latest fingerprint data, a mismatch ofthe renewed registered fingerprint data at the respective gates occursdepending on the frequency of use, and the accuracy of authenticatingpersonal identification is variable depending on the gates.

[0055] And, the fingerprint data stored in the host device 531 is thefirst one at the time of registering the fingerprint, and when enteringa room after a long period since the fingerprint was registered in agate determined according to the entrance allowing information, theregistered fingerprint data is downloaded from the host device 531. But,since the fingerprint data is not latest, it is highly possible thatchecking results in a mismatch. Since it is thought that the fingerprintis one and only and not variable, it is used to authenticate personalidentification, but it changes to some extent, and a state of thefingerprint face or the fingerprinted position varies every timefingerprinting is made, but the fingerprint data at the time ofregistering fingerprints is not always optimum. Therefore, by using theaffixed fingerprint data with the conditions according to which personalidentification can be authenticated at every fingerprinting for the nexttime, the checking probability can be improved, but as described above,there is a disadvantage that the registered fingerprint data not renewedis remained in the host device 531.

[0056] And, a fingerprint checking device has been put in practical usewhich configures a file with the identification number entered at theregistration of fingerprints and the registered fingerprint datacorresponded, and checks the registered fingerprint data read from thefile based on the identification number entered for checkingfingerprints with the affixed fingerprint to authenticate personalidentification. And, improvement of operability of such a fingerprintchecking device is demanded.

[0057] A system is known to control entrance /exit by checkingfingerprints, and to register a fingerprint, personal information suchas identification number, name, post, attribute and desired room numberis entered, and a fingerprint is affixed. And, to enter a room,identification number is entered into the fingerprint checking device,and a fingerprint is affixed. The fingerprint checking device reads theregistered fingerprint data from a file according to the enteredidentification number, checks it with the affixed fingerprint toauthenticate personal identification, and if personal identification canbe authenticated, releases the electric lock of the door to allow toenter.

[0058] Identification numbers for various systems are allocated withoutoverlapping. For example, when a single fingerprint checking device inthe entrance/exit control system can register fingerprints for 480persons, by providing 32 fingerprint checking devices, in other words,if there is 32 rooms, 15360 persons can register a fingerprint. And, toallocate the identification number to these 15360 persons withoutoverlapping, at least five digits are required. And, a larger-scaledentrance/exit control system may need the identification number of sixdigits or more.

[0059] Therefore, to enter a room, an identification number of fivedigits or six digits must be entered into the fingerprint checkingdevice. Even if a fingerprint can be checked in a short time, theentrance of an identification number takes a long time, and thefingerprint checking device for a room where entrance and exit arefrequent is particularly poor in operability.

[0060] And, the fingerprint checking device checks the previouslyregistered fingerprints with a newly affixed fingerprint to authenticatepersonal identification, and the registered fingerprint is made bystoring an area containing respective minutiae corresponding to aplurality of minutiae in multivalued image data obtained from a picturedfingerprint into a registration file. And, the binarized image dataobtained by picturing an affixed fingerprint at checking the fingerprintis compared with respective areas of the binarized image data containingthe minutiae read from the registration file, and if areas in prescribednumber or more match, it is determined as a match. Accordingly, toimprove the fingerprint checking accuracy, it is demanded to registerfingerprints having a desired accuracy.

[0061] The fingerprint has two minutiae of an ending point and abifurcation point of ridge lines, and most of fingerprint checkingdevices store the minutiae as registration data in the registrationfile. For the fingerprint registration, the multivalued image dataobtained by picturing an affixed fingerprint is binarized, the binarizedimage data is thinning-processed, the ridge lines thinning-processed areextracted with the ending points and the bifurcation points as theminutiae, the binarized image data areas are cut out according tocoordinate information of the minutiae, and they are stored as theregistered data in the registration file.

[0062]FIG. 45 is an explanatory diagram of a fingerprint checkingdevice, in which reference numeral 601 denotes an affixed fingerprintimage pickup unit, 602 a data processing unit, 603 a bus, 604 aprocessor (CPU), 605 an interface (IF), 606 a read-only memory (ROM)storing a program, 607 a multivalued image memory, 608 a binarized imagememory, 609 a binarized image save memory, 610 a thinning-processedimage memory, 611 a minutia list memory, and 612 a nonvolatile memoryfor registered data. The processor 604 controls the respective unitsconnected through a bus 603 and has a function of processing the imagedata.

[0063] The affixed fingerprint image pickup unit 601 comprises afingerprinting stand on which a fingerprint is affixed, a lightingsource, a CCD camera, a display, and an input operation unit such as aten-key which are unillustrated. To register a fingerprint, informationof an ID number and a password and a fingerprint registering request areentered through the input operation unit, a fingerprint is affixed ontothe fingerprinting stand, and the affixed fingerprint is pictured by theCCD camera. A signal of the fingerprint image pictured by the affixedfingerprint image pickup unit 601 is A/D converted by the interface 605into multivalued image data.

[0064] The memories 607 to 611 in the data processing unit 607 arecleared by initializing. And, the multivalued image data which wasA/D-converted by the interface 605 is written into the multivalued imagememory 607, the multivalued image data in the multivalued image memory607 is binarized by the data processing function of the processor 604and written into the binarized image memory 608.

[0065] The binarized image data in the binarized image memory 608 iscopied and saved into the binarized image data save memory 609. And, thecontent of the binarized image memory 608 is subjected to thinningprocessing. In other words, the ridge lines of the fingerprint arechanged into thin lines. The thinning-processed image data is writteninto the thinning-processed image memory 610. Based on thethinning-processed image data in the thinning-processed image memory610, the minutiae of the ending points and bifurcation points areextracted, and coordinate information of the minutiae is written intothe minutia list memory 611. When the number of minutiae is a prescribednumber or more, images of minutiae are cut out of the binarized imagesave memory and stored into the nonvolatile memory 612 for registrationdata together with an ID number and a password.

[0066] To check a fingerprint, an ID number and a password are enteredthrough the input operation unit of the affixed fingerprint image pickupunit 601, the fingerprint is affixed, and it is pictured. Thefingerprint image signal is stored in the multivalued image memory 607as multivalued image data in the same way as registering a fingerprint.And, the processor 604 examines the entered ID number and password, andif normal, the registered fingerprints are read from the nonvolatilememory 612 for registering, and based on the registered fingerprint inan area containing the minutiae, checked with the entered fingerprint,and if the number of matched points is equal to or more than aprescribed number, it is determined that personal identification wasauthenticated.

[0067]FIG. 46 is an explanatory view of a binarized image of afingerprint, which is obtained by digitizing the analog image signal ofthe affixed fingerprint pictured, the multivalued image data istemporarily stored in the multivalued image memory 607 as describedabove, and the multivalued image data is binarized. In the binarizedimage state, since it is not easy to extract the ending point a or thebifurcation point b, the ridge lines are changed into thin lines. FIG.47 shows an image having thin lines, and the ending point a and thebifurcation point b can be extracted easily by processing with aprocessor.

[0068] If the fingerprint image in the affixed fingerprint state is notgood, for example, if the ridge lines are seen in a separated formdespite that the ridge lines in the binarized image are continuous asindicate by c in FIG. 48(A), when the minutiae are extracted afterthinning processing, the extraction is made with such separated pointsas the ending points.

[0069] In this case, since the coordinates of the minutiae are close, itis known to delete the minutiae, which are close in a certain range or0.5 mm or below, as pseudo minutiae from the minutia list. Thus, theminutiae due to the separated points of the ridge lines indicated by cin FIG. 48(A) are deleted as pseudo minutiae.

[0070] When such pseudo minutiae are deleted, normal minutiae are alsodeleted when they are mutually close, and the number of minutiae to beregistered in the minutia list is decreased. When the binarized image ofFIG. 48(A) is changed into thin lines and the minutiae are extracted,the minutiae more than the extracted number of minutiae of therelatively good binarized image as shown in FIG. 46 can be extracted,but when pseudo minutiae are deleted, the remaining minutiae aredecreased, and a desired number of minutiae may not be obtained. Inregistering a fingerprint, a prescribed number or more of minutiae arerequired, so that the registering process may fail by the pseudo minutiadeleting process, and registering is made again.

[0071] Accordingly, for a blurred fingerprint like the binarized imageof the fingerprint as shown in FIG. 48(A), it is known to effect thespatial filtering to connect the minutiae of the ridge lines. As aresult, the binarized image as shown in FIG. 48(B) is obtained. When thebinarized image is changed into thin lines, the normal minutiae onlyremain, and minutiae in a prescribed number or more can be extracted.

[0072] For a blurred fingerprint, even when pseudo minutiae are deletedby the spatial filtering, the number of normal minutiae becomes aprescribed number or more, a failing possibility in the registeringprocess is lowered, and as compared with a case of registering with thepseudo minutiae included, the checking rate in fingerprint checking isimproved. But, when the fingerprint image has good quality and thespatial filtering is made, a possibility of converting the pseudominutiae into the normal minutiae is high.

[0073] For example, the binarized image of the fingerprint shown in FIG.49(A) has relatively good quality, and when the spatial filtering ismade when there is a crack as indicated by d, the binarized image shownin (B) is obtained, the crack indicated by d in (A) is converted into anormal minutia as indicated by e in (B) and registered.

[0074]FIG. 50(A) shows a multivalued image of a fingerprint having largecracks, and (B) shows a multivalued image which has through the spatialfiltering, and f shows a state that cracks have continued. And, when afingerprint is checked, the spatial filtering is not applied to thefingerprint image data to check with the registered fingerprints, andthe match rate of the fingerprint is high when the normal minutiaehaving a crack are registered than when the pseudo minutiae areregistered, and it becomes higher when the normal minutiae without anycrack are registered. In other words, there are cases that the matchrate of fingerprints can be improved by the spatial filter processingand the match rate cannot be improved.

SUMMARY OF THE INVENTION

[0075] It is an object of the present invention to achieve thereliability and simplicity of registering a fingerprint by indicatingthe quality of a fingerprint image by the number of pseudo minutiae.

[0076] It is another object of the present invention is to improvesecurity of a fingerprint checking entrance/exit control system inregistering a fingerprint.

[0077] It is still another object of the present invention to detect thedirection of ridge lines of a fingerprint accurately as much aspossible.

[0078] It is also another object of the present invention to remarkablyimprove security in checking a fingerprint by remedying variousdisadvantages.

[0079] It is another object of the present invention to collect renewedregistered fingerprint data by a host device and hold the registeredfingerprint data of each gate as the latest fingerprint data.

[0080] It is another object of the present invention to improve theoperability by enabling to use identification numbers having the numberof less digits.

[0081] It is another object of the present invention to register afingerprint having a high match rate by automatically applying spatialfiltering in re-registering only.

[0082] A fingerprint registering method according to the presentinvention detects normal minutiae and pseudo minutiae of a fingerprintpictured by a fingerprint image pickup unit, counts the pseudo minutiaein registering windows with the normal minutiae at almost the center,determines the average number of pseudo minutiae in registering windowsfrom a total of pseudo minutiae in all registering windows, andregisters the fingerprint when the average number of pseudo minutiae isequal to or below a threshold.

[0083] The fingerprint registering method according to the invention,when the average number of pseudo minutiae in registering windowsexceeds the threshold, instructs to register another fingerprint, andsequentially changes fingers to register until a fingerprint with theaverage number of pseudo minutiae in registering windows equal to orbelow the threshold is obtained.

[0084] The fingerprint registering method according to the invention,when the average number of pseudo minutiae in registering windowsexceeds the threshold, instructs to register another fingerprint,selects a finger having the minimum average number of pseudo minutiae asthe best finger, and registers the fingerprint of the best finger.

[0085] A fingerprint checking device according to the present inventioncomprises a fingerprint image pickup unit, an image processor unit forthinning processing a pictured image by the fingerprint image pickupunit, a minutia detecting unit for detecting normal minutiae and pseudominutiae from the thinning-processed image from the image processorunit, an average pseudo minutia calculating unit for calculating theaverage number of pseudo minutiae in all registering windows by countingthe pseudo minutiae in the registering windows with the normal minutiaeat almost the center, a registering unit for registering a fingerprint,a judging unit for comparing the average number of pseudo minutiae fromthe average pseudo minutia calculating unit with a threshold to registerthe fingerprint in the registering unit when the average number ofminutiae is equal to or below the threshold, a display unit for showingthe average number of pseudo minutiae from the average minutiaecalculating unit or information which corresponds to the average numberof pseudo minutiae, and a checking unit for checking the fingerprintregistered in the registering unit with the fingerprint pictured by thefingerprint image pickup unit.

[0086] In the fingerprint registering method according to the invention,the judging unit displays on the display unit instructions forregistering another finger when the average number of pseudo minutiaeexceeds the threshold, selects a finger having the minimum averagenumber of pseudo minutiae as the best finger when the average number ofpseudo minutiae of all fingers exceeds the threshold, and registers thefingerprint of the best finger in the registering unit.

[0087] In the fingerprint registering method according to the presentinvention, the normal minutiae and pseudo minutiae of a fingerprint aredetected, and the pseudo minutiae in registering windows with the normalminutiae at almost the center are counted. And, the average number ofpseudo minutiae in registering windows is determined by totaling pseudominutiae in all registering windows and dividing the total by the numberof registering windows. When the average number of pseudo minutiae issmaller, the quality of the fingerprint image is better, and when theaverage number of pseudo minutiae is equal to or below the threshold, itis judged that the pictured fingerprint image is good, and registeringis effected. In this case, the formal registering can be effected aftertemporarily registering and checking by the second fingerprinting.

[0088] In the fingerprint registering method according to the invention,when the average number of pseudo minutiae in the registering windowsexceeds the threshold, it is indicated that the quality of thefingerprint image is not good. Therefore, as to five fingers forexample, the fingerprint image pickup is repeated with the fingerschanged successively until the average number of pseudo minutiae becomesequal to or below the threshold, and a finger which has a good imagequality can be registered.

[0089] In the fingerprint registering method according to the invention,when fingerprint registering is sequentially effected on all fingers andthe average number of pseudo minutiae of all fingers exceeds thethreshold, the fingerprint image quality of a finger which has theminimum average number of pseudo minutiae can be judged to be best, andthe pertinent finger is selected as the best finger and its fingerprintis registered.

[0090] In the fingerprint checking device according to the invention,the fingerprint image pickup unit takes a picture of a fingerprintaffixed on an image pickup face by a CCD camera or the like, the imageprocessor unit binarizes the fingerprint image and thinning-processingit, and the minutiae detecting unit detects the normal minutiae such asbifurcation points and ending points and the pseudo minutiae such aspseudo bifurcation points and pseudo ending points. The average pseudominutia calculating unit counts pseudo minutiae in the registeringwindows with the normal minutiae at almost the center, adds up thepseudo minutiae in all registering windows, and divides the total by thenumber of registering windows to determine the average number of pseudominutiae in the registering windows.

[0091] In the fingerprint checking device according to the invention,the judging unit, when the average number of pseudo minutiae is equal toor below the threshold, judges that the fingerprint image has a goodimage quality and registers the pertinent fingerprint in the registeringunit. And, the display unit shows the average number of pseudo minutiaeor information related thereto and can indicate the fingerprint imagequality in a numerical value. And, the checking unit checks theregistered fingerprints with a fingerprint pictured by the fingerprintimage pickup unit.

[0092] In the fingerprint checking device according to the invention,the judging unit, when the fingerprint image quality is not good and theaverage number of pseudo minutiae exceeds the threshold, shows theinstructions for registering another finger on the display unit.Accordingly, operation is effected to register another finger and doneon all fingers, and when the average number of pseudo minutiae of allfingers exceed the threshold, registering is rejected, or it is judgedthat the fingerprint image quality of a finger which has the minimumaverage number of pseudo minutiae is judged to be best, and thepertinent finger is selected as the best finger and its fingerprint canbe registered in the registering unit.

[0093] A fingerprint registering method according to the inventionregisters fingerprints of a prescribed number of at least twosupervisors in a fingerprint registering device by using a fingerprintregistering key, and a person who is to register a fingerprint registersthe affixed fingerprint in the fingerprint registering device by meansof the fingerprint registering key and the registering permissionaccording to the matching of the fingerprint of at least one of theprescribed number of supervisors who have registered their fingerprints.

[0094] The fingerprint registering method according to the invention,when the fingerprint is registered in the fingerprint registeringdevice, also registers an attribute defining an accessible range ofpersons who register fingerprints, and can renew or delete thefingerprints or the attribute registered in the fingerprint registeringdevice by means of the fingerprint registering key and the registrationpermission by matching of the fingerprints of the supervisors who haveregistered their fingerprints.

[0095] The fingerprint registering method according to the invention,when the registered fingerprints of the supervisors are required to bedeleted or the attribute is required to be changed, rejects the deletionrequirement or the attribute change requirement if the deletion or theattribute change results in that the remaining number of supervisors whohave registered fingerprints becomes one or below the prescribed number.

[0096] A fingerprint checking entrance/exit control system according tothe invention comprises a fingerprint registering device for registeringa fingerprint and an attribute of a fingerprint-registering person, afingerprint checking unit for checking the fingerprints registered inthe fingerprint registering device with the affixed fingerprint, afingerprinting unit, and fingerprint checking gates containing a controlunit for controlling to unlock according to the attribute and the resultobtained by checking the fingerprint affixed on the fingerprinting unitand the fingerprint registered in the fingerprint registering device,wherein the fingerprint registering device registers a fingerprint byfingerprint registering operation by means of a fingerprint registeringkey and the allowance of registering by checking of the fingerprint ofat least one supervisor.

[0097] The fingerprint checking entrance/exit control system accordingto the invention provides the functions of the fingerprint registeringdevice on at least one of fingerprint checking gates to share thestructure of at least fingerprinting unit.

[0098] A fingerprint checking method according to the invention forbinarizing a multivalued image obtained by picturing an affixedfingerprint into a binarized image, dividing the binarized image into aplurality of blocks, determining the direction of ridge lines inrespective blocks, effecting spatial filtering of the multivalued imagealong the ridge line direction, and binarizing to extract minutiae;wherein respective picture elements in the respective blocks aredetected by using a direction detecting mask made of 3×3 pictureelements to find which of a plurality of directions they belong, thenumber of picture elements in each of the plurality of directions isdetermined, the number of picture elements in the respective directionsis converted into a vector, the maximum value in values obtained byadding respective direction components on respective vectors isdetected, and a direction corresponding to the vector showing themaximum value is judged to be the ridge line direction of the block. Forexample, directions which mutually intersect at right angles areconverted into vectors which mutually counteract, and directioncomponents are determined on the respective vectors and added up, sothat mutual cancellation is made when the number of picture elements inthe directions to intersect at right angles is same. Therefore,detection is not made in the direction of ridge lines opposite to theflow of ridge lines.

[0099] After detecting the ridge line direction of the each block, theaverage in the ridge line direction of a focused block and a pluralityof blocks around the focused block is determined to judge as the ridgeline direction of the focused block.

[0100] A fingerprint checking method according to the inventionregisters registering fingerprint data derived from extraction ofminutiae from a fingerprint, checks the registered fingerprint data withfingerprint data for checking an affixed fingerprint, and authenticatespersonal identification depending on if they match, wherein a conversionkey number is produced by a previously defined function from an enteredkey number and the content at a prescribed byte in the registeredfingerprint data, the conversion key number is inserted for storing at aprescribed byte in the registered fingerprint data, and a key numberentered at the time of checking the fingerprint is checked with a keynumber reconstructed from the conversion key number inserted at theprescribed byte of the registered fingerprint data, and the checkingfingerprint data obtained from the affixed fingerprint is checked withthe registered fingerprint data.

[0101] The key number entered and set in the key number setting registerand the content at the n-th byte of the registered fingerprint data inthe registered fingerprint data storage file are added or subtracted toproduce a conversion key number, the conversion key number is insertedat the m-th byte of the registered fingerprint data to store in a file,the content at the n-th byte is subtracted or added with respect to theconversion key number inserted at the m-th byte in the registeredfingerprint data at checking the fingerprint to reconstruct the keynumber, and the reconstructed key number is checked with the entered keynumber.

[0102] A fingerprint checking entrance/exit control system according tothe invention comprises a host device which has a file for storingpersonal information containing entrance allowing information accordingto an identification number, name and desired room number and theregistered fingerprint data in a corresponded form and a gate which hasa fingerprint checking unit for storing the personal information and theregistered fingerprint data downloaded from the file and checking withan affixed fingerprint, both connected through a local area network(LAN), wherein the fingerprint checking unit of the gate is providedwith a control unit which renews the registered fingerprint data with atime stamp added to the affixed fingerprint data when personalidentification is authenticated by checking the affixed fingerprint withthe registered fingerprint data, and the host device collects therenewed registered fingerprint data with the time stamp added of thegate, renews the registered fingerprint data and sends the renewedregistered fingerprint data to a gate which is in compliance with theentrance allowance information.

[0103] The host device has a file which stores first and secondregistered fingerprint data from a finger registering unit, and acontrol processing unit, when the second registered fingerprint data isrenewed by the latest renewed registered fingerprint data collected fromthe gate, renews the first registered fingerprint data by the secondregistered fingerprint data, and transfers the renewed second registeredfingerprint data to a gate which is in compliance with the entranceallowing information.

[0104] A fingerprint checking device according to the invention forchecking an affixed fingerprint on a fingerprinting unit with registeredfingerprint data in correspondence with normal identification numbersstored in a file comprises a local ID file which allocates a localidentification number having the number of digits smaller than thenormal identification numbers and stores the local identificationnumber, and a control unit which reads from the fingerprint dictionaryfile in the file the registered fingerprint data corresponding to thelocal identification number entered at the time of checking with theaffixed fingerprint.

[0105] The local ID file stores the local identification number andeffective time information which indicates effective time of the localidentification number in a corresponded form.

[0106] The control unit allocates a local identification number whichdoes not overlap with another local identification number registered inthe local ID file, and corresponds the registered fingerprint data whichis corresponded with the normal identification number with the localidentification number.

[0107] A fingerprint registering method according to the invention whichbinarizes a multivalued image signal obtained by picturing an affixedfingerprint, thinning-processing image data resulting from thebinarizing process, extracts minutiae based on the thinning-processedimage data, deletes pseudo minutiae from the minutiae, and when theremaining number of minutiae is equal to or above a prescribed number,registers a fingerprint having minutiae according to the binarized imagedata, wherein if the fingerprint registering in the process for thefirst time fails, spatial filtering is effected on the multivalued imagedata to continue in the ridge line direction in the fingerprintregistering process by the process for the second time and following,the spatial filtered multivalued image data is binarized andthinning-processed, the minutiae are extracted from thethinning-processed image data, the pseudo minutiae are deleted from theminutiae, and if the remaining number of minutiae is equal to or morethan a prescribed number, the fingerprint having minutiae according tothe binarized image data is registered. In other words, the firstfingerprint registering process, when the fingerprint image is good,does not need the spatial filtering to obtain the prescribed number ormore of normal minutiae. If the first registering process fails, thefingerprint image is not good, so that the spatial filtering iseffected, and minutiae are extracted.

[0108] To delete the pseudo minutiae in the fingerprint registeringprocess, when the extracted minutiae are within a prescribed area, theyare judged as pseudo minutiae, and the pseudo minutiae are deleted froma list of minutiae.

BRIEF DESCRIPTION OF THE DRAWINGS

[0109]FIG. 1 is an explanatory diagram of the embodiment of afingerprint checking device according to the present invention.

[0110]FIG. 2 is a flowchart of fingerprint registering process in anembodiment according to the invention.

[0111]FIG. 3 is a flowchart of calculating the average number of pseudominutiae in a registering window in an embodiment according to theinvention.

[0112]FIG. 4 is a flowchart of selecting the best finger in anembodiment according to the invention.

[0113]FIG. 5 is an explanatory diagram of an embodiment of a fingerprintchecking entrance/exit control system according to the invention.

[0114]FIG. 6 is a menu explanatory diagram of an embodiment according tothe invention.

[0115]FIG. 7 is a flowchart of registering a fingerprint in anembodiment according to the invention.

[0116]FIG. 8 is a flowchart of registering a new fingerprint in anembodiment according to the invention.

[0117]FIG. 9 is a flowchart of renewing in an embodiment according tothe invention.

[0118]FIG. 10 is a flowchart of deleting in an embodiment according tothe invention.

[0119]FIG. 11 is an explanatory diagram of a file in an embodimentaccording to the invention.

[0120]FIG. 12 is an explanatory diagram of judging the ridge linedirection of a fingerprint in an embodiment of a fingerprint checkingmethod according to the invention.

[0121]FIG. 13 is a flowchart of an embodiment according to theinvention.

[0122]FIG. 14 is a flowchart of an embodiment according to theinvention.

[0123]FIG. 15 is an explanatory diagram of a ridge line directionpattern by an averaging process in an embodiment according to theinvention.

[0124]FIG. 16 is an explanatory diagram of a fingerprint checking methodaccording to the invention.

[0125]FIG. 17 is a flowchart of registering a fingerprint in anembodiment according to the invention.

[0126]FIG. 18 is a flowchart of checking a fingerprint in an embodimentaccording to the invention.

[0127]FIG. 19 is an explanatory diagram of an embodiment of afingerprint checking entrance/exit control system according to theinvention.

[0128]FIG. 20 is a flowchart of registering.

[0129]FIG. 21 is an explanatory diagram of a file.

[0130]FIG. 22 is a flowchart of checking a fingerprint.

[0131]FIG. 44 is an explanatory diagram of a fingerprint checkingentrance/exit control system.

[0132]FIG. 23 is an explanatory diagram of an embodiment of afingerprint checking device according to the invention.

[0133]FIG. 24 is an explanatory diagram of a fingerprint affixing part,a ten-key and a display.

[0134]FIG. 25 is a flowchart of new registering.

[0135]FIG. 26 is a flowchart of requiring a local ID.

[0136]FIG. 27 is a flowchart of issuing a local ID having the maximumdigits or below.

[0137]FIG. 28 is a flowchart of checking a fingerprint by entering alocal ID.

[0138]FIG. 29 is a flowchart of an embodiment of a fingerprintregistering method according to the invention.

[0139]FIG. 30 is a flowchart of registering a fingerprint according toprior art.

[0140]FIG. 31 is an explanatory diagram of normal minutiae and pseudominutiae.

[0141]FIG. 32 is an explanatory diagram of a fingerprint image and athinning-processed image.

[0142]FIG. 33 is an explanatory diagram of a fingerprint image and athinning-processed image.

[0143]FIG. 34 is an explanatory diagram of a system.

[0144]FIG. 35 is an explanatory diagram of a fingerprint checkingdevice.

[0145]FIG. 36 is an explanatory diagram of dividing a pictured imageinto blocks.

[0146]FIG. 37 is an explanatory diagram of judging the direction ofpicture elements.

[0147]FIG. 38 is a flowchart of prior art.

[0148]FIG. 39 is an explanatory diagram of detecting the direction ofridge lines according to prior art.

[0149]FIG. 40 is an explanatory diagram of detecting the direction ofridge lines according to prior art.

[0150]FIG. 41 is an explanatory diagram of a disadvantage of prior art.

[0151]FIG. 42 is an explanatory diagram of a fingerprint checkingsystem.

[0152]FIG. 43 is an explanatory diagram of extracting a keynumber-stored area according to prior art.

[0153]FIG. 45 is an explanatory diagram of a fingerprint checkingdevice.

[0154]FIG. 46 is an explanatory diagram of a binarized image of afingerprint.

[0155]FIG. 47 is an explanatory diagram of a thinning-processed image ofa fingerprint.

[0156]FIG. 48 is an explanatory diagram of a blurred fingerprint.

[0157]FIG. 49 is an explanatory diagram of a binarized image of afingerprint.

[0158]FIG. 50 is an explanatory diagram of a multivalued image of afingerprint.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

[0159]FIG. 1 is an explanatory diagram of an embodiment of a fingerprintchecking device according to the present invention, in which referencenumeral 1 denotes a fingerprint image pickup unit, 2 an image processorunit, 3 a minutia detecting unit, 4 an average pseudo minutiacalculating unit, 5 a judging unit, 6 a registering unit, 7 a displayunit, 8 a checking unit, 9 a multivalued-image capturing unit, 10 abinarized-image converting unit, and 11 a thinning-processing unit. Thefingerprint image pickup unit 1 can apply various types of knownconfigurations, and is generally configured that a fingerprint affixingsurface is illuminated by a light source and the light reflected on thesurface of a finger is pictured by a CCD camera.

[0160] The image processing unit 2 digitizes a fingerprint image fromthe fingerprint image pickup unit 1 into a multivalued level by themultivalued-image capturing unit 9 and binarized by the binarized-imageconverting unit 10. And, the binarized fingerprint image isthinning-processed by the thinning-processing unit 11. For example, asto a binarized image, the ridge lines of a fingerprint are convertedinto lines of about one picture element as shown in FIG. 31, FIG. 32 andFIG. 33(b) according to the judging processing whether or not theadjacent picture elements with respect to the focused picture element atthe center are continuous by using a 3×3 picture element mask.

[0161] The minutia detecting unit 3 detects the thinning-processedfingerprint image for bifurcation points where a prescribed number ofpicture elements are continuous or ending points where there areintervals of a prescribed number of picture elements as normal minutiae,and detects bifurcation points and ending points under other conditionsas pseudo minutiae. In such a case, by using the above-described 3×3picture element mask for example, the picture elements in theneighborhood of the focused picture elements at the center can be judgedwhether or not they are continuous or bifurcated, so that respectiveminutiae can be detected.

[0162] With respect to a registering window with the normal minutia bythe minutia detecting unit 3 at almost the center, e.g., the registeringwindow shown in a rectangular form in the thinning-processed image inFIG. 31(B), the average pseudo minutia calculating unit 4 calculatespseudo minutiae, e.g., the pseudo minutiae shown at P1 to P4 in FIG.31(C), adds up the number of pseudo minutiae of all registering windows,and dividing the total by the number of registering windows to determinethe average number of pseudo minutiae of the registering windows.

[0163] The judging unit 5 judges that a fingerprint image is good whenthe average number of pseudo minutiae is equal to or less than athreshold, e.g., 5. For example, the number of pseudo minutiae in theregistering window shown in FIG. 31(C) is four, and when it is assumedthat the average number of pseudo minutiae is also four, it is equal toor less than the threshold. In such a case, the fingerprint image shownin FIG. 31(A) is judged to be of a good image quality, and the pertinentfingerprint is registered in the registering unit 6. In this case,coordinate information of the registering windows containing the normalminutia and the binarized image within the registering windows areregistered. And, the registering unit 6 can apply various types ofstorage devices such as a semiconductor integrated circuit memory and amagnetic disk drive.

[0164] Display unit 7 can be formed of a liquid crystal display device,a CRT display device or the like, and shows the above-described averagenumber of pseudo minutiae, or indicates that the fingerprint image has apoor image quality as the average number of pseudo minutiae increases,so that the image quality can be converted into a numerical value anddisplayed. Information on the possibility of registering can also beindicated. When the average number of pseudo minutiae exceeds athreshold in the judging unit 5, it can be displayed to register anotherfinger. When the fingerprint of a best finger is registered, the bestfinger can be displayed as the registered finger.

[0165] After registering a fingerprint in the registering unit 6, thechecking unit 8 checks the fingerprint pictured by the fingerprint imagepickup unit 1 with the registered fingerprint, and when they match, itis judged as personal identification. And, it can be applied to varioustypes of security devices. The functions of the above-described unitscan be achieved by the individual configurations of the respective unitsor by a calculating function of a processor or a memory.

[0166]FIG. 2 is a flowchart of registering a fingerprint in theembodiment of the present invention, in which n denotes the number offingers to be registered. For example, a first finger is indicated by 0,a second finger by 1, and a third finger by 2. And, m[ ] is an addressof a memory for storing the average number of pseudo minutiae. Forexample, an address for storing the average number of pseudo minutiae ofa first finger is m[0], and an address for storing the average number ofpseudo minutiae of a second finger is m[1].

[0167] First, when n=0 (A1), it is judged whether or not fingerprintinghas been made (A2), and if fingerprinting has been made, the averagenumber of pseudo minutiae in the registering window is calculated by theaverage pseudo minutia calculating unit 4 (see FIG. 1) (A3). Thisaverage number of pseudo minutiae is stored in an address m[0] of thememory. And, it is judged whether or not the average number of pseudominutia is equal to or less than the threshold by the judging unit 5(A5). When the average number of pseudo minutia is equal to or less thanthe threshold, it is judged that the fingerprint image is good, and theformal registering is made (A7). Otherwise, temporary registering andchecking (A15) are performed before the formal registering, and if theymatch, the formal registering can be made.

[0168] When the average number of pseudo minutiae exceeds the threshold,the average number of pseudo minutiae is shown on the display unit 7(A8). In this case, the average number of pseudo minutiae is displayedas a numerical value, or it can be displayed in percentage indicatingthe image quality.

[0169] In accordance with what is displayed, it is judged whether or notregistering of another finger has been instructed (A9), and if theinstructions for registering another finger have been made, the numberof fingers n to be registered is stored as +1, and processing goes tostep (A2).

[0170] When repeated registering of all fingers has been completed,there is no instructions for registering another finger remain, so thatit is judged whether or not there is any instructions for registeringthe best finger (A10), and when there is such instructions, selection ofthe best finger is performed (A11). And, the fingerprint of the bestfinger selected by the best finger selecting process is registered.

[0171] If there is not any instructions for registering the best finger,it is judged whether or not there is forced registering instructions(A12). In other words, when the average number of pseudo minutiae of thefingerprints of all fingers exceeds the threshold, a desired finger canbe designated to make the forced registering instructions, and thefingerprint of the designated finger is registered. In this case, in thesame way as prior art, the temporary registering and the checkingaccording to the affixed fingerprint are performed, and when thetemporarily registered fingerprint and the affixed fingerprint match,processing goes to the formal registering (A7), and when they do notmatch, registering can be rejected. If there is not forced registeringinstructions, it is judged whether or not there is a forced terminationinstruction (A13), and if there is such an instruction, processing isforced to be terminated, and if there is not, processing goes to step(A9).

[0172]FIG. 3 is a flowchart of calculating the average number of pseudominutiae in the registering window in the embodiment of the invention,in which an image signal from the fingerprint image pickup unit 1 isconverted into a multivalued digital signal and captured by themultivalued image capturing unit 9 of the image processor unit 2 (B1),it is converted into a binarized image by the binarized-image convertingunit 10 (B2), it is then masked and thinning-processed by thethinning-processing unit 11 as described above (B3), minutiae areextracted based on the thinning-processed image by the minutia detectingunit 3 (B4), pseudo minutiae are detected (B5), and normal minutiae forregistering are extracted (B6).

[0173] Then, in the average pseudo minutia calculating unit 4, thenumber of pseudo minutiae within the registering window with the normalminutiae at about the center is calculated (B7), a total of pseudominutiae in all registering windows is calculated (B8), and the total isdivided by the number of registering windows to obtain the averagenumber of pseudo minutiae (B9). Such calculation can be performed at ahigh speed by combining the already known addition with shifting.

[0174]FIG. 4 is a flowchart of selecting the best finger in theembodiment of the invention, indicating the step (A11) of FIG. 2 indetail. In the drawing, reference numeral n_(t) denotes the content of acounter which is used to select the best finger, and m_(t) the averagenumber of pseudo minutiae. When the average number of pseudo minutiae inthe registering windows exceeds the threshold and no instructions forregistering another finger is given, n_(t)=0 (C1), then m_(t)=m [0](C2), and the average number of pseudo minutiae m for the first fingeris read to judge whether or not m_(t)>m [n_(t)] (C3).

[0175] And, when m_(t)>m [n_(t)] m_(t)←m [n_(t)] (C4), and it is judgedwhether or not n_(t)=n (C5). Even when it is not m_(t)>m [n_(t)], it isjudged whether or not n_(t)=n. And, when n_(t)=n, the finger which isindicated by n_(t) is determined as the best finger and registered (C7).When n_(t)≠n, n_(t) is counted up (C6), and processing goes to step(C3). Thus, among all fingers, the finger having the minimum averagepseudo minutia which is not satisfactory as the fingerprint image istemporarily selected as the best finger, and its fingerprint isregistered. In this case, the name and number of the best finger areshown on the display unit 7 to notice a fingerprint registeringoperator. Accordingly, the selected best finger may be affixed to checka fingerprint.

Embodiment 2

[0176]FIG. 5 is an explanatory diagram of the embodiment of afingerprint checking entrance/exit control system according to thepresent invention, in which reference numeral 21 denotes a fingerprintregistering device, 22 a fingerprint checking unit, 23 and 25 a modem,24 a private branch exchange (PBX), 26-1 to 26-n a fingerprint checkinggate, 27 a control unit, 28 a clock, 29 a fingerprinting unit, 30 adisplay unit, 31 a ten-key, 32 a relay, 33 an interface, 34-1 to 34-n anelectric lock of the door to a room where entrance and exit are made orof allowing to operate a computer which stores significant data.

[0177] The fingerprint registering device 21 comprises an unillustratedkeyboard such as a ten-key, a key hole for a fingerprint registeringkey, a fingerprinting part, a fingerprint registering part and a displayto indicate guidance. To start to use the system, at least twosupervisors (system administrator) are selected, the fingerprint of eachsupervisor is registered by using the fingerprint registering key, thena new fingerprint registering person other than the supervisors insertsthe fingerprint registering key, and at least one supervisor affixes hisor her fingerprint on the fingerprinting part, and when the supervisor sregistered fingerprint matches with the affixed fingerprint and the newfingerprint registering person affixes his or her fingerprint on thefingerprinting part, data such as the identification number, post, name,attribute and accessible door entered through the keyboard and thefingerprint can be registered.

[0178] Specifically, the new fingerprint registering person can use thefingerprint registering key upon being approved to register afingerprint by the supervisor, and by the fingerprint registeringapproval by the direct fingerprint checking of the supervisor, thefingerprint can be registered in the fingerprint registering device 21.Thus, since the fingerprint of the new fingerprint registering personcan be registered under the double guards of the fingerprint registeringkey and the fingerprint checking of the supervisor, security of thefingerprints registered in the fingerprint registering device 21 can beimproved.

[0179] The fingerprint checking unit 22 checks the registeredfingerprints with the affixed fingerprint, and can be composed of a hostcomputer. Since the fingerprint checking unit 22 and the fingerprintregistering device 21 have a common function in processing thefingerprint, they can be achieved by the same computer.

[0180] The fingerprint checking gates 26-1 to 26-n comprise the modem25, the control unit 27 configured of a microprocessor, the clock 28configured of a hard clock or soft clock, the fingerprinting unit 29configured of a light source and a CCD camera, the display unit 30 suchas a liquid crystal panel, the ten-key 31 for entering an ID or thelike, the relay 32 used for an unillustrated power switch for thedevice, and the interface 33 for releasing or locking the electric lock;and are provided for a room where entrance and exit are made of acomputer.

[0181] And, the fingerprint checking unit 22 and the fingerprintchecking gates 26-1 to 26-n are connected through the private branchexchange 24 but may be connected by a dedicated line to form the system.And, by providing a fingerprint checking unit which has the samefunctions as the fingerprint checking unit 22 and a storage unit whichreceives and stores online or off-line the fingerprint data stored inthe fingerprint registering device 21, the registered fingerprints andthe affixed fingerprint can be checked separately at the fingerprintchecking gates 26-1 to 26-n.

[0182] When a fingerprint is affixed on the fingerprinting unit 29, afingerprint image signal obtained by picturing the fingerprint under thecontrol of the control unit 27 is transferred to the fingerprintchecking unit 22 through the modem 25, the private branch exchange 24and the modem 23. The fingerprint checking unit 22 checks it with theregistered fingerprints in the fingerprint registering device 21, andsends back the checked result to the fingerprint checking gate.Otherwise, at the fingerprint checking gate which has the fingerprintchecking unit, the affixed fingerprint and the registered fingerprintscan be checked without transferring the fingerprint image signal.

[0183] If they match, the control unit 27 releases the electric lockthrough the interface 33. When the accessible door is limited at thetime of registering a fingerprint, it is judged whether or not thefingerprint matches at the fingerprint checking gate for the accessibledoor, and if the fingerprint matches for the accessible door, theentrance is allowed. And, if the fingerprint affixed to thefingerprinting unit 29 does not match with any registered fingerprint,it is shown on the display unit 30, and the electric lock is notreleased. Therefore, if a person does not have his or her fingerprintregistered, the affixed fingerprint does not match with the registeredfingerprints and the entrance is not allowed. And, when the fingerprintchecking gate is provided for a computer, the computer cannot be usedwhen the fingerprints do not match.

[0184]FIG. 6 is an explanatory diagram of a menu in the embodimentaccording to the invention, showing one example of the operation menu onthe side of the fingerprint checking unit 22 to control the entrance andexit (see FIG. 5). An initial menu 1-1 includes menus such asfingerprint registration 2-1, registered data transmission 2-2, entrancerecord collection 2-3, printing/monitoring 2-4, setting 2-5,unconditional unlocking 2-6, forced open monitoring 2-7, fingerprintingcounter 2-8, backup 2-9, and termination 2-10. Among them, thefingerprint registering 2-1, setting 2-5, unconditional unlocking 2-6,fingerprinting counter 2-8, and termination 2-10 can be operated by thesupervisor (system manager) only.

[0185]FIG. 7 is a flowchart of registering a fingerprint in theembodiment according to the invention, showing the registering of thefingerprint in the fingerprint registering device 21 shown in FIG. 5.The fingerprint registration 2-1 of the menu of FIG. 6 shown on thefingerprint registering device 21 is designated. In registering thefingerprint, the fingerprint registering key is needed, and it is judgedwhether or not the fingerprint registering key is turned on (A1). Whenthe fingerprint registering key is not inserted or it is inserted butnot turned on, a message “Turn on the key.” is displayed, and theinitial menu 1-1 resumes (A11).

[0186] When the fingerprint registering key is turned on, it is judgedwhether or not the fingerprints of at least two supervisors have beenregistered. Since the supervisors have the fingerprints registered togive approval for registering a new fingerprint, if there is only onesupervisor at the time of operating the system and any accident takesplace, subsequent new registering, renewal or deletion of a fingerprintcannot be made, so that at least two supervisors are registered withoutreservation. Therefore, in step (A2), it is judged whether or not twosupervisors have been registered, and if not, the fingerprints of twosupervisors are registered without reservation.

[0187] When a fingerprint is registered after registering thefingerprints of two supervisors, the fingerprint registering key isturned on, the fingerprints of the supervisors are affixed, it is judgedwhether or not the supervisors could be identified by checking thefingerprints (A5), and if the identification cannot be made, a message“Not identified. Unless the supervisors are identified, this menu cannotbe used.” is displayed (A6), and the initial menu 1-1 resumes (A11).

[0188] When the supervisors are identified, processing goes to theselection of processing (A7), and new 2-1-1 (A8), renewal 2-1-2 (A9),deletion 2-1-3 (A10), or initial menu 1-1 (A11) is selected. And, afterreturning to initial menu 1-1, registered data transmission 2-2 (A12) isautomatically selected and transmitted to the fingerprint checking gate.

[0189]FIG. 8 is a flowchart of registering a new fingerprint in theembodiment according to the invention, showing that the fingerprintregistration 2-1 in the menu of FIG. 6 is selected, and new 2-1-2 (A8)of FIG. 7 is selected. The fingerprints of two supervisors have beenregistered, and the ID, post, name, use condition, attribute andaccessible door of a fingerprint registering person are entered (B1).The attribute in this case generally indicates an operator of thecomputer or a supervisor managing the system. And, the accessible doormeans a computer room, a room number or a door. As to the supervisor whohas first registered a fingerprint, the ID, post and name are entered,the attribute is automatically determined as the supervisor, and theaccessible door can be selected.

[0190] Upon completing the above-described entry, a message “Newregistering (Y/N)” is displayed (B2). And, a key indicating YES or NO isoperated, and it is judged which key is operated (B3). If the NO key isoperated and new registering is not effected, processing goes to step(B1), and when the YES key is operated and new registering is effected,the affixed fingerprint is captured (B4), and the attribute entered instep (B1) is judged.

[0191] And, when the attribute is general, general new registering (B6)is effected, when it is the operator, operator new registering (B7) iseffected, and when it is the supervisor, supervisor new registering (B8)is effected. When the number of supervisors registered is limited, thenumber of registered supervisors is judged, and if it exceeds aprescribed number, registering of a fingerprint with the attribute ofthe supervisor designated is rejected.

[0192] Then, new registered data is shown (B9), it is checked by the newfingerprint registering person, a message “Continue new registering?(Y/N)” is shown (B10), it is judged which key has been operated (B11),if a discontinue key is operated, menu of fingerprint registering 2-1resumes (B12). and if continue menu is operated, step (B1) resumes.

[0193]FIG. 9 is a flowchart of renewing in the embodiment according tothe invention, showing the selection of renewal 2-1-2 of FIG. 7, and amessage “Enter ID to be renewed.” is shown (Cl). And, when the ID to berenewed is entered, registered data containing the post, name, usecondition, attribute, accessible door as well as the renewed ID is shown(C2).

[0194] And, selection is judged (C3), and when other is selected,renewal item is entered (C5), and processing goes to step (C1). And,when termination is selected, a message “Renew (Y/N)” is shown (C4), itis judged which key has been operated for entry (C5), if a non-renewalkey is operated, processing goes to step (C15), and if a renewal key isoperated, the affixed fingerprint is captured (C9), and the attribute isjudged (C10).

[0195] When the attribute is general, operator or supervisor, thegeneral renewing (C11), operator renewing (C12) or supervisor renewing(C13) is performed, renewed data is shown (C14) to allow the check ofthe renewed content, and a message “Continue renewing? (Y/N)” is shown(C15), it is judged which key has been operated (C16), and when anon-renewal key is operated, processing returns to the menu offingerprint registering 2-1 (C17), and when a renewing key is operated,processing returns to step (C1). In the supervisor renewing (C13), whenrenewal of the attribute results in that the number of remainingregistered supervisors does not meet the prescribed number of at leasttwo, the pertinent attribute renewal request is rejected.

[0196]FIG. 10 is a flowchart of deleting in the embodiment according tothe invention, showing the detection of deletion 2-1-3 in FIG. 7, andaccording to a message “Enter ID to be deleted.” (D1), the ID to bedeleted is entered. Data of the pertinent ID, post, name, use condition,attribute and accessible door is shown (D2). And, a message “Delete(Y/N)” is shown (D3), it is judged which key has been operated (D4), ifa non-deletion key has been operated, processing goes to step (D10), andif a deletion key has been operated, the attribute is judged (D5), andaccording to the attribute, general deleting (D6), operator deleting(D7) or supervisor deleting (D8) is performed, and deletion data isshown for confirmation (D9).

[0197] In the supervisor deleting (D8), when the deletion remains two ormore supervisors, deletion is performed, but if it is one, deletion isrejected. It can be determined that the number of remained supervisorsis a prescribed number of at least two, and if the remaining supervisorsmay be less than the prescribed number, the pertinent supervisordeletion request can be rejected.

[0198] Then, a message “Continue deleting? (Y/N)” is displayed (D10),and it is judged which key has been operated in response (D11). When anon-continuing key has been operated, processing returns to the menu offingerprint registering 2-1 (D12), and when the continuing key has beenoperated, processing returns to step (D1).

[0199] As described above, according to the fingerprint registering keyand the supervisor fingerprint checking, new registering, renewal ordeletion of the fingerprint can be made, security of the registeredfingerprints under the double guards can be improved, and safety ofentrance and exit according to the registered fingerprints can besecured.

[0200]FIG. 11 is an explanatory diagram of files in the embodimentaccording to the invention, containing a registering number of peoplemanagement file 41, a personal information file 42 and a fingerprintdictionary file 43. The registering number of people management file 41manages the number of people having fingerprints registered according tothe attributes of supervisor, operator and general. And, the personalinformation file 42 registers the contents of respective items of ID,name, attribute, and accessible door entered at the time of registeringfingerprints. And, the fingerprint dictionary file 43 contains afingerprint dictionary in correspondence with the ID, and thefingerprint dictionary registers fingerprints by known means usingminutiae of fingerprints to form a checking dictionary.

[0201] Therefore, in step (A2) of FIG. 7, it is easy to judge whether ornot the registered number of supervisors has exceeded two by referringto the registering number of people management file 41. And, in the caseof the new registering shown in FIG. 8, the number of peoplecorresponding to the attributes of the registered number of people file21 is added, and the ID, name, attribute and accessible door for newregistering is added to the personal information file 42, and the ID andfingerprint for new registering are added to the fingerprint dictionaryfile 43.

[0202] In the case of renewal shown in FIG. 9, to renew the attribute,the number of people with the pertinent attributes given in theregistering number of people managing file 41 is renewed. In such acase, the number of supervisors is checked, and when the registerednumber of supervisors renewed keeps the prescribed number of two ormore, the renewal of the attributes of the supervisors is approved, andwhen the registered number of supervisors becomes below the prescribednumber by renewing from the attributes of the supervisors to otherattributes, it can be controlled to reject the renewal. And, thepersonal information file 42, when the renewal is approved, is renewedaccording to the contents of the renewal registration. The fingerprintdictionary file 43 has the pertinent ID renewed.

[0203] In the case of deletion shown in FIG. 10, the number of peoplewith the pertinent attribute in the registering number of peoplemanaging file 41 is subtracted. In such a case, the number ofsupervisors is checked, and when the number of supervisors afterdeleting is the prescribed number of at least two, the deletion isapproved, and when it is below the prescribed number of at least two, itcan be controlled that deletion is not approved. And, the personalinformation file 42 deletes the pertinent data when the deletion isapproved. And, the fingerprint dictionary file 43 has the pertinent IDdeleted.

[0204] At the time of registering a fingerprint and checking afingerprint in the entrance and exit control, by referring to theabove-described file, security in registering, renewing or deleting afingerprint and security of entrance and exit control can be improved.

Embodiment 3

[0205]FIG. 12 is an explanatory diagram of judging the ridge linedirections of a fingerprint in the embodiment of a fingerprint checkingmethod according to the invention. For example, as shown in FIG. 37, thedirections of respective picture elements in the block are detected tobelong to which of the directions 1 to 8 shown at the lower right in thedrawing by using a direction detecting mask formed of 3×3 pictureelements. And, the picture element is added for every directions(inclinations) 1 to 8. The contents of a totaling register showing thenumber of picture elements added to correspond with the directions 1 to8 at that time are indicated as vectors V1 to V8. In other words, thenumber of picture elements added in the direction 1 of FIG. 37 isvector * V1, the number of picture elements added in the direction 2 isvector * V2, the number of picture elements added in the direction 3 isvector * V3, and as described above, the directions which intersects atright angles like the directions 1 and 5 are determined as mutuallyoffsetting directional vectors like vector * V1 and vector * 5.

[0206] And, with respect to the vector * V1, a component in thedirection of * V1 of vectors * V2 to * V8 is determined and added. Forexample, the component in the direction of * V1 of vector * V2 is V2indicated by a dotted arrow, and the component in the direction of * V1of vector * V8 is V8 indicated by a dotted arrow. And, vectors * V3, *V7 intersect with vector * V1 at right angles, so that the component inthe direction of * V1 is zero. And, since vector * V5 is in thedirection of 180 degrees with respect to vector * V1, the component inthe direction of * V1 is −V5. Besides, the component in the directionof * V1 of vector * V1 is −V4 as indicated by a dotted arrow, thecomponent in the direction * V1 of vector * V6 is −V6 as indicated by adotted arrow. Therefore, when the component in the direction of * V1 isadded, R1=V1+V2+V8−V4−V6.

[0207] Similarly, as to the directions of vectors * V2 to * V8, R2 to R8are determined with the components in the respective directions added,and the direction which has the maximum value among the added results R1to R8 is determined as the direction of ridge lines in the block. Forexample, when the number of picture elements of vectors * V1, * V3 ismany, the number of picture elements of vector * V2 is smaller thanthat, and the number of picture elements of other vectors * V4 to * V8is much smaller than that, the direction of vector * V1 or * V3 isdetermined as the direction of ridge lines in prior art. But, since theadded result of the component in the direction * V2 is the maximumvalue, the direction of * V2 between vectors * V1 and * V3 is determinedas the direction of ridge lines.

[0208]FIG. 13 and FIG. 14 show a flowchart in the embodiment accordingto the invention. In steps (A1) to (A8), in the same way as shown insteps (B1) to (B8) of prior art shown in FIG. 38, block number m andpicture element number n in the block are determined to be an initialvalue 1, the content of the totaling register corresponding to adirection is determined to be an initial value 0, and the direction ofpicture element P_(m. n) (m=1˜1024, n=1˜256) is detected by using adirection detecting mask made of 3×3 picture elements. And, as to thebinarized image of a finger, a histogram of picture elements in theblock is produced in respective directions.

[0209] Then, it is determined that R=V1. Specifically,direction-oriented totaling register content V1 is determined to beregister R. And, it is determined that j=i+1 (A10), and j is compensated(A11). When i=1, this j compensation is indicated as j=i+1=2, indicatingvector * V2 at 45 degrees with respect to vector * V1, but when i=8, itis j=8+1=9, so that it is judged whether or not j exceeds 8, and if jexceeds 8, processing to satisfy j=j−8 is indicated.

[0210] And, totaling register content Vj in direction j is multiplied by½^(½) to determine a component in direction j, and it is added to theregister R (A12). For example, as to the V1 direction component ofvector * V2, since * V2 is in a direction of 45 degrees with respectto * V1, V2 indicated by a dotted arrow is obtained by multiplying * V2by ½^(½). Namely, step (A12) shows to add this V2 to V1.

[0211] Then, it is determined that j=i+7 (A13), and j is compensated(A14). In this case, when i=1, then j=8. But, when i=2, then j=2+7=9.Therefore, when j>8, compensation for j=j−8 is effected. And, in thesame way as step (A12), addition of R=R+(Vj/2^(½)) is effected todetermine V1 direction component of Vj (A15). In this case, it is shownthat when i=1, addition is effected to determine a V1 directioncomponent V8 of V8 in FIG. 1.

[0212] When it is determined that j=j+3 (A16), the same j compensationas in steps (A11), (A14) is effected (A17). In this case, when i=1, thenj=4, and since the * V1 direction component V4 of * V4 is in thedirection opposite from * V1, it is determined to be −V14−V4, and(V1−V4) is calculated. Step (A18) shows this processing.

[0213] It is then determined that j=j+5 (A19), and the j compensation iseffected in the same way as in steps (A11), (A14) and (A17) (A20), andthe same calculation as in step (A18) is effected (A21). Then, whenj=j+4 (A22), the same j compensation as above is effected (A23), andcalculation of R=R−Vj is effected (A24). In this case, when i=1, thenj=5, and it means vector * V5 in FIG. 12. Since * V5 is in the direction180 degrees opposite from * V1, the * V1 direction component of * V5becomes −V5, so that processing of V1−V5 is performed.

[0214] And, it is judged whether or not Sm<R (A25). In other words, thecontent Sm of the maximum valued register for each block is comparedwith the content R of the totaling register and when Sm<R, the contentSm of the maximum valued register is converted into the content R of thetotaling register (A26), and the content Dm of the direction register isdetermined as the direction i at the time (A27).

[0215] And, when it is not Sm<R and next to step (A27), it is judgedwhether or not i=8 (A28). In other words, it is judged whether or notprocessing has been completed in the directions 1 to 8, and if not, itis determined that i=i+1 (A29), and processing goes to step (A9). And,if it has been completed, it is judged whether or not m=1024 (A3).Namely, it is judged whether or not processing on 1 to 1024 blocks hasbeen completed, and if not, then m=m+1 (A31), and processing goes tostep (A2). If it has completed, the content Sm of the maximum valuedregister corresponding to the block is fixed as the maximum value. And,the direction corresponding to the maximum value is stored in thedirection register Dm.

[0216] The pattern in the direction of ridge lines corresponding to theblock thus obtained is along the flow of the ridge lines, and byeffecting the spatial filtering based on it, occurrence of a bridgebetween the ridge lines as in prior art can be prevented.

[0217] As to the pattern in the direction of ridge lines correspondingto the block, to further smooth the flow of ridge lines, a 3×3 blockstructured mask is used to determine the average of the focused blocksat the center and the peripheral blocks in the direction of ridge lines,so that it can be determined as the direction of ridge lines of thefocused blocks.

[0218]FIG. 15 is an explanatory diagram of a pattern in the direction ofridge lines by averaging processing in the embodiment of the invention.As described above, a 3×3 block configured mask is used to determine theaverage of ridge line directions in the focus blocks. It is apparent bycomparing the pattern of FIG. 15 with the pattern shown in FIG. 39(C) orFIG. 41(A) that the flow of ridge lines is smoothed by the averagingprocess in the embodiment according to the invention, it is used toeffect the spatial filtering, and binarizing is performed, so thataccurate minutiae of a fingerprint can be extracted easily.

[0219] The above-described embodiment is a case that the pictureelements in each block of the binarized image are in eight directions,but not limited to such directions and may be four or six directions fordetection. And, the added value of picture elements in each direction isexpressed in vector, addition is effected to determine the directioncomponent for each vector, and the direction where such added valuebecomes maximum can be determined as the direction of ridge lines of thepertinent block.

Embodiment 4

[0220]FIG. 16 is an explanatory diagram of the embodiment of afingerprint checking method according to the present invention, in whicha conversion key number s is produced by a previously defined functionby a computing unit 53 such as an adder, subtracter, multiplier orscientific calculator from a content d at the n-th byte of fingerprintdata in a registered fingerprint data storage file 51 and a key number kset for a key number setting register 52, and it is inserted at the m-thbyte of the fingerprint data. And, FIG. 16 also shows a state with adata destruction checking code added. In this case, n, m and k are keptconfidential, and n and m can be any arbitrary value and determined inadvance.

[0221] For example, when it is assumed that the content d at the n-thbyte of the registered fingerprint data is 18_((h)) in hexadecimalnotation, the key number k which is entered through a keyboard orten-key and set for the key number setting register 52 is 7(h), and thecomputing unit 53 is an adder, then s=d+k=18_((h))+7_((h))=1F_((h)), andthe conversion key number s is inserted at the m-th byte of theregistered fingerprint data.

[0222] When the key number k=7_((h)) is entered to check a fingerprint,the fingerprint checking device reads the content d=18_((h)) at the n-thbyte of the registered fingerprint data and the conversion key numbers=F(h) at the m-th byte, the computing unit 3 is operated as asubtracter, and the key number k can be reconstructed by computingk=s−d=1F_((h))−18_((h))=7_((h)), so that the reconstructed key number kis checked with the entered key number, and when they match, checking ofthe affixed fingerprint and the registered fingerprints are started.But, if the key number does not match, it is judged not to be a normalfingerprint check, and the subsequent processing is rejected.

[0223] The computing unit 53 functions as an adder at the time ofproducing a conversion key number and as a subtracter at the time ofreconstructing the conversion key number, but it can be functioned as asubtracter at the time of producing the conversion key number and as anadder at the time of reconstructing the conversion key number. It isalso possible to perform various functional calculations such as theabove-described addition or deduction by multiplying the entered keynumber k or the content d at the n-th byte by a constant, and a methodof effecting various functional calculations can be applied inaccordance with the system. Accordingly, even when the conversion keynumber s is read, the reconstruction of the key number k can bedisabled.

[0224] As described above, since the conversion key number is storedtogether with the registered fingerprint data, the registeredfingerprint data has a random property even when the fingerprintregistering is repeated with the entered key number constant,possibility is low that the content d at the n-th byte of the registeredfingerprint data becomes same, and the conversion key number variesevery time a fingerprint is registered. Therefore, as described inconnection with FIG. 5, even when the registered fingerprint data ischecked after entering the same key number to register a fingerprint, itis impossible to find a position where the key number is inserted uponmatching. And, if the registered fingerprint data is altered, theconversion key number cannot be reconstructed, so that misuse can beprevented.

[0225]FIG. 17 is a flowchart of registering a fingerprint in theembodiment according to the invention, in which it is judged whether ornot the key number k has been set for the key number setting register 52(A1), and if it has been set, fingerprinting is instructed (A5), but ifnot, the entry of the key number is instructed (A2).

[0226] After instructing the entry of the key number, it is judgedwhether or not the key number has been entered (A3), if the key numberhas been entered, the key number k is stored in the key number settingregister 2 (A4), and processing goes to step (A5). And, it is judgedwhether or not the fingerprinting has been detected (A6), and if thefingerprinting is detected, the registered fingerprint data is producedin view of the extracted minutiae (A7).

[0227] And, the content d at the n-th byte of the registered fingerprintdata is stored in the register (A8), the conversion key number s isproduced by calculating, e.g., s=d+k by the computing unit 53 (A9), theconversion key number s is inserted at the m-th byte of the registeredfingerprint data (A10), and the registered fingerprint data is stored inthe file (A11).

[0228]FIG. 18 is a flowchart of checking a fingerprint in the embodimentaccording to the invention, in which it is judged whether or not the keynumber has been set (B1), if it has not been set, entry of the keynumber is instructed (B2), it is judged whether or not the entry of thekey number has completed (B3), and when the key number is entered inaccordance with the instructions for entering the key number, the keynumber k is stored in the register (B4).

[0229] When the key number has been set or it has been entered, thecontent d at the n-th byte of the registered fingerprint data is readand stored in the register (B5), then the conversion key number s in thecontent at the m-th byte of the registered fingerprint data is read andstored in the register (B6), and the conversion key number s isreconstructed by the computing unit 53. For example, the key number k isreconstructed as k=s−d, and the reconstructed key number k is checkedwith the entered key number (B7).

[0230] If they do not match, check rejection processing is effected(B12). For example, a message “Key numbers do not match.” is displayed,and the subsequent processing is canceled. And, when they match,fingerprinting is instructed (B8), and it is judged whether or notfingerprinting is detected (B9), if fingerprinting is detected, afingerprint is checked according to some known method (B10), and thechecked result is noticed (B11). For example, when the enteredfingerprint matches, an unlocking signal is sent to allow the entrance.

Embodiment 5

[0231]FIG. 19 is an explanatory diagram in the embodiment of afingerprint checking entrance/exit control system according to theinvention, in which reference numeral 61 denotes a host device, 62-1 to62-n a gate, 63 a line for a local area network (LAN) or the like, 64 afingerprint registering unit, 65 a control processing unit, 66 a file,67 and 78 an interface (IF), 71 a control unit, 72 a file, 73 afingerprinting unit, 74 a display unit, 75 a ten-key, 76 a clock unit,and 77 an electric lock.

[0232] The host device 61 is connected with a plurality of gates 61-1 to61-n through the line 63 to form the fingerprint checking entrance/exitsystem, and a fingerprint registering device can be connected to theline as shown in FIG. 44. And, at the time of registering a fingerprintby the fingerprint registering unit 64 of the host device 61, personalinformation of name, post, identification number (ID) and entranceallowing information according to desired room number are entered, and afingerprint is affixed. The personal information entered at the time ofregistering the fingerprint is stored in the personal information fileof the file 66, the fingerprint data formed by extracting minutiae ofthe affixed fingerprint is stored in a fingerprint dictionary file, andthe identification number (ID) corresponding to the room numberaccording to the entrance allowing information is stored in a possessedID file.

[0233] The control processing unit 65 controls the fingerprintregistering in the fingerprint registering unit 64, the production ofthe personal information file, fingerprint dictionary file and possessedID file in the file 66, the collection of renewal registered fingerprintdata at the gates 62-1 to 62-n, and the transmission of the renewalregistered fingerprint data to the gates with reference to the possessedID file. For example, the above-described functions can be achieved by aprogram-controlled processor.

[0234] The gates 62-1 to 62-n indicate the control of an electric lock77 for allowing the opening or closing of a door, but can also beapplied when the use of a specified device such as a computer is allowedby checking a fingerprint by providing the electric lock which allows touse the device. And, the file 72 is for storing personal information andregistered fingerprint data downloaded from the file 66 of the hostdevice 61, and the control unit 71 configures a fingerprint checkingunit for checking the registered fingerprint data stored in the file 72with a fingerprint affixed on the fingerprinting unit 73, controls torelease the electric lock 77 when personal identification isauthenticated by checking the fingerprint, adds a time stamp accordingto time indicated by the clock unit 76, controls to renew the registeredfingerprint data stored in the file 72 by the affixed fingerprint data,and upon the request from the host device 61, controls to send renewalregistered fingerprint data. For example, such functions can be achievedby a program-controlled processor.

[0235]FIG. 20 is a flowchart of registering, in which personalinformation such as name, identification number (ID), post and desiredroom number is entered into the fingerprint registering unit 64 of thehost device 61 or the fingerprint registering device not shown in FIG.19 (A2), and the first fingerprinting is effected (A2). Fingerprint dataaccording to the first fingerprinting is temporarily registered (A3).Then, the second fingerprinting is effected (A4). And, the fingerprintdata according to the first fingerprinting is checked with fingerprintdata according to the second fingerprinting to judge whether or not theymatch (A5). In other words, they are mutually checked as registeredfingerprint data and affixed fingerprint data, and when the personalidentification is authenticated, it is judged as acceptance, and if itis judged as rejection, the registering operation is determined asfailure (A7). In this case, the fingerprint registering operation iseffected from beginning.

[0236] And, if matched in the fingerprint checking, the controlprocessing unit 65 controls to produce the file 66 (A6). In other words,the personal information file, the fingerprint dictionary filecontaining the first registered fingerprint data according to the firstfingerprinting and the second registered fingerprint data according tothe second fingerprinting, and the possessed ID file prepared accordingto entrance allowing information are prepared. And, the fingerprintdictionary file is transferred to the setting gate according to thepossessed IF file (A8). In this case, transmission is made with theidentification number (ID) of personal information corresponding to theregistered fingerprint data added. Otherwise, it can be controlled totransmit upon request for the registered fingerprint data based on theidentification number (ID) from the gates 62-1 to 62-n.

[0237]FIG. 21 is an explanatory diagram of a file, showing an example ofa personal information file 81, a fingerprint dictionary file 82 and apossessed ID file 83. And, the personal information file 81 shows a caseof ID=ida, name=OGABW, post=GPRJ and entering room numbers=G1˜Gn, and asupervisor enabling to use the host device or attribute such as generalpersonnel who are not allowed to use can be stored. And, informationsuch as operation records of personal information can also be stored.

[0238] And, the fingerprint dictionary file 82 shows a case of ID=ida,registered fingerprint data=RD1, RD2, and time stamps=TS1, TS2. In otherwords, first registered fingerprint data RD1 according to the firstfingerprinting at registering the fingerprint and second registeredfingerprint data RD2 according to the second fingerprinting are stored.And, the possessed ID file 83 has fingerprint-registered IDs stored incorrespondence with the gates G1 to Gn. For example, the gate G1 shows acase that IDs such as ida, idb and ide are set, and ID=ida is set forall gates G1 to Gn.

[0239]FIG. 22 is a flowchart of checking a fingerprint, in which firstan ID is entered through the ten-key 75 at the gate for a room to beentered (B1), and a fingerprint is affixed to the fingerprinting unit 73(B2). In this case, a message according to the operation order can beshown on the display unit 74. And, the control unit 71 judges whether ornot registered fingerprint data corresponding to the entered ID is inthe file 72 (B3), and if not, transfers the fingerprint dictionary file(B4). In other words, the address of the host device 61 is added, and aregistered fingerprint data requiring signal containing the ID and thegate address is sent to the line 63 through the interface 78.

[0240] The host device 61 receives the registered fingerprint datarequiring signal through the interface 67, reads the registeredfingerprint data corresponding to the ID from the file 66, and sends tothe line 63 through the interface 67 with the gate address added. Thegate requiring the registered fingerprint data receives the registeredfingerprint data through the interface 18 and stores in the file 12.Thus, download of the registered fingerprint data is completed.

[0241] And, the affixed fingerprint is checked with the first registeredfingerprint data (B5), it is judged whether or not personalidentification has been authenticated (B6), and if not authenticated,the affixed fingerprint is checked with the second registeredfingerprint data (B8), it is judged whether or not personalidentification has been authenticated (B9), and if not authenticated,fingerprint checking is terminated because personal identification cannot be authenticated even by the second fingerprint checking, and, it isshown on the display unit 74 that checking has failed.

[0242] When personal identification is authenticated in step (B6), thefirst registered fingerprint data is renewed by the affixed fingerprintdata (B7). And, when personal identification is authenticated in step(B9), the second registered fingerprint data is renewed by the affixedfingerprint data (B10). And, a time stamp according to the time of theclock unit 76 is added to the renewed fingerprint data (B11). In thiscase, date can also be contained in addition to time.

[0243] And, according to periodical collection of renewal fingerprintdata from the host device 61, the control unit 71 refers to the timestamp added to the renewal registered fingerprint data of the file 72 oruses the flag already sent to the host device 61, identifies renewalregistered fingerprint data not sent to the host device 61, and sendsthe renewal registered fingerprint data, the time stamp and the ID tothe host device 61. The host device 61 renews the fingerprint dictionaryfile according to the ID of the collected renewal registered fingerprintdata. In this case, the time stamp is referred to, and even when therenewal registered fingerprint data of a time stamp older than the timestamp already renewed is collected, renewal is not effected according toit.

[0244] As to the fingerprint dictionary file 82 shown in FIG. 21, thetime stamp added to the collected renewal registered fingerprint data isreferred to, and when the time stamp is latest, the first registeredfingerprint data RD1 is renewed according to the second registeredfingerprint data RD2, and the second registered fingerprint data RD2 isrenewed according to the collected renewal recorded fingerprint data.Therefore, the fingerprint dictionary file 82 in the file 66 of the hostdevice 61 stores the latest renewal registered fingerprint data and theprevious renewal registered fingerprint data.

[0245] The host device 61, upon completion of renewing the fingerprintdictionary file 82, refers to the possessed ID file 83, and sends therenewed registered fingerprint data to the gate having the ID having therenewed registered fingerprint data (B12). Thus, without increasing thedata transmission volume through the line 3 between the host device 61and the respective gates 61-1 to 62-n, the registered fingerprint datastored in the fingerprint dictionary file of the file 33 according tothe host device 61 can be determined to be identical with the registeredfingerprint data which corresponds to the gate with the entering roomdetermined.

[0246] In steps (B3) to (B11), in the same way of renewing thefingerprint dictionary file 82 of the file 66 in the host device 61, itcan be controlled so that the second registered fingerprint data isrenewed by the affixed fingerprint data, and the first registeredfingerprint data is renewed by the second registering fingerprint data.And, as to the system using one registered fingerprint datacorresponding to ID, a study function of renewing the registeredfingerprint data by the affixed fingerprint data can be applied whenpersonal identification is authenticated. And, a data transmissionformat between the host device 61 and the gates 62-1 to 62-n can beselected in accordance with the use of a public circuit or LAN for theline 63.

Embodiment 6

[0247]FIG. 23 is an explanatory diagram in the embodiment of afingerprint checking device according to the invention, in whichreference numeral 91 denotes a fingerprint checking device, 92 a controlunit, 93 a fingerprinting unit, 94 a display unit, 95 a ten-key, 96 aclock unit, 97 a control output unit, 98 a file, 99 a fingerprintdictionary file, 100 a personal information file, 101 a local ID file,102 an interface (IF), and 103 a line such as a local area network (LAN)or public circuit.

[0248] Multiple fingerprint checking devices 91 are connected throughthe line 103, and an unillustrated host device is also connected to formthe entrance/exit control system. In such a case, when personalidentification is authenticated by checking a fingerprint, an unlockingsignal is given to an unillustrated electric lock from the controloutput unit 7, and the lock is released to allow entrance. And, the hostdevice has personal information such as name, post, desired room number,identification number (hereinafter called “ID”) and registeredfingerprint data in correspondence with the ID, and the personalinformation and the registered fingerprint data can be downloaded intothe file 98 of the fingerprint checking device 91 through the line 103.And, such control means is already known.

[0249] Into the fingerprint dictionary file 99 of the file 98, theabove-described registered fingerprint data is stored, and personalinformation is stored in the personal information file 100. The normalID in the personal information and the registered fingerprint data inthe fingerprint dictionary file 99 are mutually linked and stored, andthe normal ID is entered from the ten-key 95, so that the control unit92 can read the registered fingerprint data corresponding to the enterednormal ID from the fingerprint dictionary file 99 and check with theaffixed fingerprint. And, the local ID file 101 is for storing a localID having the number of digits smaller than the ID used for registeringa fingerprint, namely, the normal ID. This local ID is allocated so asnot to overlap.

[0250]FIG. 24 is an explanatory diagram of the fingerprinting unit,ten-key and display unit, in which the fingerprinting unit 93 indicatesa finger positioning stand, and an unillustrated CCD camera and alighting source are positioned below it. And, the display unit 94 ismade of a liquid crystal display panel, and a message “Enter ID.” isdisplayed as shown in the drawing. It is also possible to display theposition of a finger on the fingerprinting unit 93, so that a finger canbe guided to a proper position. And, the ten-key 95 has function keysother than those illustrated.

[0251]FIG. 25 is a flowchart of new registering, showing that when thereis provided the fingerprint registering unit of an unillustrated hostdevice, a device dedicated for fingerprint registering, or afingerprinting unit provided on the fingerprint checking device, thefingerprint registering and the local ID registering are effected by thefingerprint registering unit. First, an ID is entered (A1), it is judgedwhether or not the ID has been registered (A2), if it has beenregistered, it is displayed that it cannot be used because it has beenregistered and overlaps (A3), and processing returns to the first step.

[0252] If the entered ID has not been registered, personal informationsuch as post, name and accessible door number is entered (A4), andpersonal information containing the ID is registered (A5). Then, it isjudged whether or not it is local ID setting (A6), and if not,processing goes to fingerprint registering (A12). If it is local IDsetting, a local ID is entered (A7), accessible door number is entered(A8), it is judged whether or not it is a registered local ID (A9), andif it is a registered local ID, it is displayed that it becomes anoverlapped local ID (A10), and processing goes to step (A6) to allow theentry of another local ID.

[0253] If it is not a registered local ID, the entered local ID isregistered (A11), and processing goes to fingerprint registering (A12).This fingerprint registering can apply some already known means, forexample, an image obtained by picturing an affixed fingerprint isbinarized, minutiae such as bifurcation points are extracted to preparefingerprint data, such data is determined to be registered fingerprintdata and stored in a file in connection with the ID. And, it is judgedwhether or not new registering is continued (A13), and if the newregistering is continued, processing goes to step (A1), and if it is notcontinued, processing is terminated.

[0254] This local ID, if “0” is not allocated, can be a single digitwhen nine or less people want to enter a room. In such a case, the samelocal ID can be determined for a desired room. For example, when thenormal ID is “32145” and the local ID “3” is determined for a pluralityof rooms, the entry of the one-digit local ID and fingerprinting aresufficient, so that operability is improved remarkably.

[0255] When “0” and “00” are not allocated for the local ID, a 2-digitlocal ID can be allocated to 99 or smaller people who want to enter aroom. And, as described above, when the maximum number of registeredfingerprint data which can be stored in a single fingerprint checkingdevice is 480, three digits are sufficient to allocate a local ID tothem. Therefore, when a particular normal ID is allocated to at least10000 people, the normal ID has at least five digits, but by allocatingthe local ID, the number of digits can be sufficient to be smaller thanthe normal ID, so that the entry of ID is easy for fingerprint checking.

[0256]FIG. 26 is a flowchart of requiring a local ID, showing that afterregistering an ID and a fingerprint, a local ID is set in thefingerprint checking device or a fingerprint registering device, and theeffective period of the local ID is determined. In other words, thelocal ID requirement is entered (B1), and an n-digit normal ID isentered (B2). And, a fingerprint is affixed (B3), and it is checked toauthenticate personal identification (B4). If the checked result is NG,it means that the entry of the normal ID is wrong or the subject personis not the right one for the normal ID, and processing goes to step(B2).

[0257] If the checked result is OK, an n digit local ID with aneffective time set is issued. In this case, it means that N<n, and thefingerprint checking side allocates the local ID while avoidingoverlapping. And, the effective time also shows to previously determineby the fingerprint checking device, and various types of effective timesetting means of a method which keeps all issued local IDs effectiveuntil the same time or a method which issues a local ID and keeps iteffective for a prescribed period can be adopted according to theproperties of the system.

[0258]FIG. 27 shows a flowchart of issuing a local ID having the maximumdigits or below, in which it is assumed that the normal ID has thenumber of digits n, the local ID has the number of digits n and thelocal ID has the maximum number of digits m, it is meaningless to issuethe local ID having the number of digits n=m, so that the local IDhaving the number of digits n>m is issued. First, initialization iseffected with the number of digits n of the local ID 1 (C1), it isjudged whether or not the number of digits n of the local ID to beissued is equal to or less than the maximum number of digits m (C2), andif the number of digits n of the local ID is not equal to or less thanthe maximum number of digits m, the local ID cannot be issued (C3), andprocessing of issuing the local ID is terminated.

[0259] When the number of digits n of the local ID is equal to or lessthan the maximum number of digits m, it is judged whether or not thereis any unused or invalid local ID (C4), and if there is not any, thenumber of digits n of the local ID is increased by one digit (n←n+1),and processing goes to step (C2). And, if there is, its local ID andeffective time are displayed. Then, the effective time of the local IDto be issued and the normal ID corresponding to the local ID are renewed(C7).

[0260] For example, in the fingerprint checking device 91 shown in FIG.23, a code or the like for the local ID requirement is entered from theten-key 95, the normal ID is entered, and a fingerprint is affixed onthe fingerprinting unit 93, the control unit 92 refers to the file 98 tocheck the fingerprint, and if personal identification is authenticated,refers to the local ID file 11, and issues the local ID by steps (C1) to(C7) of FIG. 27. The effective time at the time can be set according tothe current time indicated by the clock unit 96. And, the effective timeand the local ID are shown on the display unit 94, and it can beconfirmed by entering through the ten-key 95 or the like.

[0261]FIG. 28 is a flowchart of checking a fingerprint by entering alocal ID, in which when an n digit local ID is entered through theten-key 95 (D1), the control unit 92 refers to a local ID file 101 toread effective time information corresponding to the entered local ID,reads the current time information from the clock unit 96, and judgeswhether or not the entered local ID is before the effective time (D2).

[0262] If the effective time has passed, a message “Effective time haspassed.” is shown on the display unit 94 (D3), and processing isterminated. And, if within the effective time, the normal IDcorresponding to the local ID is displayed on the display unit 94 (D4).Thus, it can be checked whether or not the entry of the local ID iswrong. This step can be omitted, and the instructions for fingerprintingcan be displayed.

[0263] And, when a fingerprint is affixed on the fingerprinting unit 93(D5), the control unit 92 which identifies the normal ID correspondingto the local ID reads registered fingerprint data corresponding to thenormal ID from the fingerprint dictionary file 99, checks it with theaffixed fingerprint, and if the checked result is NG, displays it on thedisplay unit 94, and terminates processing, but if the checked result isOK, outputs the result of personal identification (D7), and sends anunlocking signal corresponding to the electric lock from the controloutput unit 97 for example.

[0264] The present invention is not limited to the above-describedembodiments. For example, in the local ID registering process shown inFIG. 25, effective time can be set. Similarly, in the local ID issuingprocess shown in FIG. 27, an arbitrary local ID is entered, it is judgedby the control unit 92 whether or not the pertinent local ID has beenissued, the judged result is displayed on the display unit 94, and theentered local ID can be set in the local ID file in correspondence withthe normal ID, or the entering can be made again. And, the registeredfingerprint data stored in the fingerprint dictionary file 99 is linkedwith the normal ID stored in the personal information file 100, so thatthe local ID set in the local ID file and the normal ID are linked, thenormal ID is determined from the entered local ID, the registeredfingerprint data is read according to the normal ID, so that thefingerprint can be checked. But, by directly linking the local ID withthe registered fingerprint data, the registered fingerprint datacorresponding to the entered local ID can be read from the fingerprintdictionary file 99 to check the fingerprint.

Embodiment 7

[0265]FIG. 29 is a flowchart of the embodiment of a fingerprintregistering method according to the present invention, in which (1) to(15) show steps of registering a fingerprint. The fingerprintregistering method will be described with reference to the structureshown in FIG. 45.

[0266] First, when registering of a fingerprint is started, it is judgedwhether or not fingerprinting has been made (1), if the average level ina prescribed range of the image signal by a fingerprint image pickupunit 111 is equal to or above a prescribed value, it is judged thatfingerprinting has been made, and multivalued fingerprint image dataobtained by A/D-converting the pictured image signal by an interface 115is written into a multivalued image memory 117 (2). Multivalued imagedata in the content of the multivalued image memory 117 is binarized andwritten into a binarized image memory 118 (3), and the binarized imagedata in the content of the binarized image memory 118 is copied into abinarized image save memory 119 (4).

[0267] Then, it is judged whether or not the registering operation isfor the first time (5), and if it is the first time, processing goes tothinning processing (8), the binarized image data in the content of thebinarized image memory 118 is thinning-processed to change the ridgelines of the fingerprint into thin lines and written into athinning-processed image memory 110, the thinning-processed image datais used to extract minutiae of ending points or bifurcation points ofridge lines, the extracted minutia points (coordinate information) arewritten into a minutia list memory 111 (9), the minutiae in a prescribedrange, e.g., 0.5 mm, are deleted as pseudo minutiae from the minutialist memory 111 (10).

[0268] And, it is judged whether or not the remaining minutiae are equalto or above a prescribed number (11), and if they are equal to or abovethe prescribed number, the image at the minutia part is taken out of thebinarized image save memory 119 based on the coordinate information ofminutiae and written into a nonvolatile memory 112 for registering data(12). Thus, the fingerprint registering process is completed (13).

[0269] If the number of minutiae is less than the prescribed number, itis judged whether or not the number of registering operations is for thethird time (13), and if it is the third time, registering is determinedas failure. This number of times may be set to four or five. And, if itis not the third time, processing goes to step (1), and fingerprintingand registering steps (1) to (4) are performed. And, in this case, whenthe registering is not the first time in step (5) and the fingerprintimage is judged to be defective, the spatial filtering is effected onthe multivalued image data in the content of the multivalued imagememory 117 (6). The multivalued image data undergone the spatialfiltering is written into the multivalued image memory 117, and thecontent of the multivalued image memory 117 is renewed.

[0270] The above-described spatial filtering judges the direction ofridge lines and processes to connect the spaces of a prescribed numberof picture elements or below in the direction of ridge lines. Forexample, the multivalued image data is binarized, one screen is dividedinto block areas having a prescribed number of picture elements, thedirection of ridge lines in each block area is judged according to thepicture element arrangement pattern in each block area, and theprescribed number of picture elements is expanded in the direction ofridge lines with respect to the multivalued image data to connect cracksor the like. Therefore, for example, the cracks in the multivalued imageshown in FIG. 50(A) are connected as marked by f in FIG. 50(B) by thespatial filtering.

[0271] The multivalued image data which is through the spatial filteringin the multivalued image memory 7 is binarized and written into thebinarized image memory 9 (7). Therefore, the content of the binarizedimage memory 9 written in step (3) is renewed. And, processing goes tostep (8), and thinning processing, extraction of minutiae and deletionof pseudo minutiae are performed in steps (8) to (10), it is judgedwhether or not the remaining number of minutiae is equal to or above aprescribed number (11), and if it is so, the image at the minutia pointsis taken out of the binarized image save memory 119 based on thecoordinate information of minutiae and written into the nonvolatilememory 112 for registering data (12). Thus, the fingerprint registeringis completed (13).

[0272] If the number of remaining minutiae is not equal to or more thanthe prescribed number, it is judged whether or not the number ofregistering times is third (14), and if not, processing goes to step(1). If it is the third time, it is determined as registering failure(15). This number of registering times can be identified easily byproviding a simple-structured counter.

[0273] When the pictured fingerprint image is relatively good, e.g., asshown in FIG. 46 (A), there are partial cracks but the prescribed numberof minutiae can be obtained by deleting such cracks as pseudo minutiae,then the normal minutiae are registered, so that the fingerprintchecking rate can be improved.

[0274] When the pictured fingerprint image is not good, e.g., when themultivalued image shown in FIG. 50(A) is binarized andthinning-processed to extract minutiae, the number of pseudo minutiaeincreases and the prescribed number or more of minutiae cannot beobtained by deleting the pseudo minutiae, then the spatial filtering isperformed to obtain the multivalued image as shown in FIG. 50(B), forexample. Then, it is binarized and thinning-processed to extract theminutiae. In this case, the number of pseudo minutiae is decreased, thedeletion of the normal minutiae by the pseudo minutia deleting processcan be avoided, a probability of obtaining the prescribed number or moreof minutiae is enhanced, and a failure in registering the fingerprintcan be prevented.

[0275] The prescribed number of minutiae in step (11) can be set to,e.g., 10 to 20, and it can be selected in accordance with the accuracyof fingerprint checking. The repeating frequency of registeringoperation, when the number of remaining minutiae is not equal to or morethan the prescribed number, can be increased as required becauseidentification can be made by means of a counter as described above.

Industrial Applicability

[0276] The fingerprint registering method and fingerprint checkingdevice according to the present invention have advantages that theaverage number of pseudo minutiae in registering windows is determinedat the time of registering a fingerprint, the average number of pseudominutiae is small when the fingerprint image has a good image qualitywhile it is large when the image quality is not good, so that anumerical value can be used to indicate whether or not the fingerprintimage is good; when it is equal to or less than a threshold, thefingerprint image can be judged to be registerable, and the probabilityof matching between the registered fingerprint with the affixedfingerprint is not lowered with the lapse of time.

[0277] And, even when multiple number of fingers are registered and allfingerprint images are NG because the average number of pseudo minutiaeexceeds the threshold, a finger having the minimum average number ofpseudo minutiae can be selected as the best finger and its fingerprintcan be registered, so that by automatically selecting the best fingeramong fingers having chaps or many wrinkles, the application range offingerprint checking can be expanded and the fingerprint checking can bemade more accurate.

[0278] The fingerprint registering method and fingerprint checkingentrance/exit control system according to the present invention requiresto use a fingerprint registering key to register the fingerprints of atleast two supervisors in the fingerprint registering device, allows toregister a new fingerprint of a person by the fingerprint registeringkey and the matching of the fingerprints of the supervisors, and can beoperated for other menus such as registering, renewal and deletion of afingerprint for entrance/exit control and collection of entrance/exitrecord under double guards by the fingerprint registering key and thefingerprint matching of the supervisors, thereby improving security forentrance/exit control.

[0279] As to the supervisors, in renewing or deleting an attribute, whenthe remaining supervisor is one or less than a prescribed number, arequest for renewing or deleting the attribute is rejected, so that thesupervisors who are required at the time of registering, renewing ordeleting a fingerprint are firmly secured, so that the fingerprintchecking entrance/exit control system can be operated smoothly.

[0280] The fingerprint checking method according to the inventiondetects the direction of respective picture elements in respectiveblocks of a binarized fingerprint image by a direction detecting mask,converts the number of picture elements having picture elements added tocorrespond to the direction into a vector, adds respective vectors todetermine respective direction components, determines the vectordirection which becomes the maximum added value as the ridge linedirection of the pertinent block, and can detect the ridge linedirection for each block according to the flow of ridge lines ascompared with prior art which judges as the ridge line direction adirection in which the number of picture elements merely correspondingto a direction is maximum. Therefore, when the spatial filtering isperformed based on the ridge line direction to provide a multivaluedimage and it is binarized, the minutiae of the fingerprint can beaccurately extracted from the binarized image, so that it isadvantageous in improving the accuracy of checking a fingerprint.

[0281] The fingerprint checking method according to the presentinvention produces a conversion key number s based on an entered keynumber k and a content d at the n-th byte of registered fingerprintdata, and inserts the conversion key number s at the m-th byte of theregistered fingerprint data to store in a file, so that even when afingerprint is registered by using the same key number k, it issubstantially impossible to find where the conversion key number s isinserted when the values n, m are not known. Accordingly, the key numberfor checking a fingerprint does not match with respect to alteration orthe like of fingerprint registering data, and it is advantageous inimproving reliability in view of the entrance/exit control by checking afingerprint and the operation control of the device or the like.

[0282] The fingerprint checking entrance/exit control system accordingto the present invention is an entrance/exit control system fordistributed processing in which a host device and a plurality of gatesare connected through a line and fingerprint checking is effected byeach gate fingerprint checking unit, wherein registered fingerprint datais renewed by affixed fingerprint data at the time of personalidentification, a time stamp for indicating the pertinent time is addedand kept, renewal registered fingerprint data is sent upon a periodicalrequirement from the host device, the host device refers to the timestamp according to the collected renewal registered fingerprint data torenew the fingerprint dictionary file, and renewal registeredfingerprint data corresponding to an ID is sent to the gates set tocorrespond to the ID, so that it has an advantage that registeredfingerprint data at respective parts can be kept as the same.

[0283] The fingerprint checking device according to the presentinvention has advantages to allocate a local ID having the number ofdigits smaller than that of a normal ID to simplify the entry operationin checking a fingerprint and to improve operability. And, by settingeffective time for the local ID, the local ID allocated to a person whooften uses temporarily can be allocated to other persons after the lapseof effective time, thus the local ID having the less number of digitscan be used effectively.

[0284] The fingerprint registering method according to the presentinvention processes assuming that the fingerprint image is good in afirst fingerprint registering operation, and if the number of minutiaeremaining after deleting pseudo minutiae is less than a prescribednumber, judges that the fingerprint image is NG, and operates toregister again. In such a case, the spatial filtering is effected tomake a fingerprint image which has a less number of pseudo minutiae, sothat the finger registering operation seldom fails and the fingerprintmatching rate can be improved by registering normal minutiae.

What is claimed is:
 1. A fingerprint registering method comprising: detecting normal minutiae and pseudo minutiae of a fingerprint pictured by a fingerprint image pickup unit, counting the number of said pseudo minutiae in registering windows with said normal minutiae at almost the center, determining the average number of pseudo minutiae in the registering windows from a total of pseudo minutiae in all registering windows, and registering said fingerprint when said average number of pseudo minutiae is equal to or below a threshold.
 2. The fingerprint registering method according to claim 1 , wherein when said average number of pseudo minutiae in the registering windows exceeds the threshold, registering of another fingerprint is instructed, and fingers are sequentially registered until a fingerprint with the average number of pseudo minutiae in the registering windows equal to or below the threshold is obtained.
 3. The fingerprint registering method according to claim 1 , wherein when said average number of pseudo minutiae in the registering windows exceeds the threshold, registering of another fingerprint is instructed, a finger having the minimum average number of pseudo minutiae in the registering windows is selected as the best finger, and the fingerprint of said best finger is registered.
 4. A fingerprint checking device comprising: a fingerprint image pickup unit, an image processor unit for thinning processing a pictured image by said fingerprint image pickup unit, a minutia detecting unit for detecting normal minutiae and pseudo minutiae from the thinning-processed image from said image processor unit, an average pseudo minutia calculating unit for calculating the average number of pseudo minutiae in all registering windows by counting said pseudo minutiae in the registering windows with said normal minutiae at almost the center, a registering unit for registering a fingerprint, a judging unit for comparing said average number of pseudo minutiae from said average pseudo minutia calculating unit with a threshold to register the fingerprint in said registering unit when said average number of pseudo minutiae is equal to or below said threshold, a display unit for showing said average number of pseudo minutiae from said average minutiae calculating unit or information which corresponds to said average number of pseudo minutiae, and a checking unit for checking the fingerprint registered in said registering unit with the fingerprint pictured by said fingerprint image pickup unit.
 5. The fingerprint checking device according to claim 4 , wherein said judging unit displays on said display unit instructions for registering another finger when said average number of pseudo minutiae exceeds said threshold, selects a finger having the minimum average number of pseudo minutiae as the best finger when the average number of pseudo minutiae of all fingers exceeds said threshold, and registers the fingerprint of said best finger in said registering unit.
 6. A fingerprint registering method for a system to release a lock by checking an affixed fingerprint with a registered fingerprint, in which fingerprints of a prescribed number of at least two supervisors are registered in a fingerprint registering unit by using a fingerprint registering key, and a person who is next to register a fingerprint registers the fingerprint in said fingerprint registering device by means of the fingerprint registering key and the matching of the fingerprint of at least one of said prescribed number of supervisors who have registered their fingerprints.
 7. The fingerprint registering method according to claim 6 , wherein when the fingerprint is registered in said fingerprint registering device, an attribute defining an accessible range of persons who register fingerprints is also registered, the fingerprints or said attribute registered in said fingerprint registering device can be renewed or deleted by means of the fingerprint registering key and the registration permission by matching of the fingerprints of said supervisors who have registered their fingerprints.
 8. The fingerprint registering method according to claim 6 to 7, wherein when the registered fingerprints of said supervisors are required to be deleted or the attribute is required to be changed, said deletion requirement or the attribute change requirement is rejected if the deletion or the attribute change results in that the remaining number of supervisors who have registered fingerprints becomes one or below the prescribed number.
 9. A fingerprint checking entrance/exit control system for unlocking by checking an affixed fingerprint and a registered fingerprint comprising: a fingerprint registering device for registering a fingerprint and an attribute of a fingerprint registering person, a fingerprint checking unit for checking the fingerprints registered in said fingerprint registering device with the affixed fingerprint, a fingerprinting unit, and fingerprint checking gates containing a control unit for controlling to unlock according to said attribute and the result obtained by checking the fingerprint affixed on said fingerprinting unit and the fingerprint registered in said fingerprint registering device, wherein said fingerprint registering device registers a fingerprint by fingerprint registering operation by means of a fingerprint registering key and the allowance of registering by checking of the fingerprint of at least one supervisor.
 10. The fingerprint checking entrance/exit control system according to claim 9 , wherein the functions of said fingerprint registering device are provided on at least one of said fingerprint checking gates to share the structure of at least fingerprinting unit.
 11. A fingerprint checking method for binarizing a multivalued image obtained by picturing an affixed fingerprint into a binarized image, dividing said binarized image into a plurality of blocks, determining the direction of ridge lines in respective blocks, effecting spatial filtering of said multivalued image along the ridge line direction, and binarizing to extract minutiae, wherein respective picture elements in said respective blocks are detected by using a direction detecting mask to find to which of a plurality of directions they belong, the number of picture elements in each of said plurality of directions is determined, the number of picture elements in said respective directions is converted into a vector, the maximum value in values obtained by adding respective direction components on respective vectors is detected, and a direction corresponding to the vector showing said maximum value is judged to be the ridge line direction of said block.
 12. The fingerprint checking method according to claim 11 , wherein after detecting the ridge line direction of said each block, the average in the ridge line direction of a focused block and a plurality of blocks around said focused block is determined to judge as the ridge line direction of said focused block.
 13. A fingerprint checking method which registers fingerprint data derived from extraction of minutiae from a fingerprint, checks said registered fingerprint data with fingerprint data for checking an affixed fingerprint, and authenticates personal identification if they match, wherein a conversion key number is produced by a previously defined function from an entered key number and the content at a prescribed byte in said registered fingerprint data, said conversion key number is inserted for storing at a prescribed byte in said registered fingerprint data, and a key number entered at the time of checking the fingerprint is checked with a key number reconstructed from said conversion key number inserted at the prescribed byte of said registered fingerprint data, and the checking fingerprint data obtained from the affixed fingerprint is checked with said registered fingerprint data.
 14. The fingerprint checking method according to claim 13 , wherein said entered key number and the content at the n-th byte of said registered fingerprint data are added or subtracted to produce a conversion key number, said conversion key number is inserted at the m-th byte of said registered fingerprint data to store in a file, the content at said n-th byte is subtracted or added with respect to said conversion key number inserted at the m-th byte in said registered fingerprint data at checking the fingerprint to reconstruct the key number, and said reconstructed key number is checked with the entered key number.
 15. A fingerprint checking entrance/exit control system comprising a host device which has a file for storing personal information containing an identification number and entrance allowing information and registered fingerprint data in a corresponded form and a gate which has a fingerprint checking unit for storing said personal information and said registered fingerprint data downloaded from the file in said host device and checking with an affixed fingerprint, both connected through a line, wherein the fingerprint checking unit of said gate is provided with a control unit which renews said registered fingerprint data with a time stamp added to said affixed fingerprint data when personal identification is authenticated by checking said affixed fingerprint with said registered fingerprint data, and said host device collects the renewed registered fingerprint data with the time stamp added of said gate, renews the registered fingerprint data and sends said renewed registered fingerprint data to a gate which is in compliance with entrance allowance information of said personal information.
 16. The fingerprint checking entrance/exit control system according to claim 15 , wherein said host device has a file which stores first and second registered fingerprint data from a finger registering unit, and a control processing unit, when said second registered fingerprint data is renewed by the latest renewed registered fingerprint data collected from said gate, renews said first registered fingerprint data by said second registered fingerprint data, and transfers said renewed second registered fingerprint data to a gate which is in compliance with said entrance allowing information.
 17. A fingerprint checking device for checking an affixed fingerprint on a fingerprinting unit with registered fingerprint data in correspondence with normal identification numbers stored in a file, characterized by comprising: a local ID file which allocates a local identification number having the less number of digits than said normal identification numbers and stores said local identification number, and a control unit which reads from said file said registered fingerprint data corresponding to said local identification number entered at the time of checking the fingerprint and checks with said affixed fingerprint.
 18. The fingerprint checking device according to claim 17 , wherein said local ID file stores said local identification number and effective time information which indicates effective time of said local identification number in a corresponded form.
 19. The fingerprint checking device according to claim 17 or 18 , wherein said control unit allocates a local identification number which does not overlap with another local identification number registered in said local ID file, and corresponds said registered fingerprint data, which is corresponded with said normal identification number, with said local identification number.
 20. A fingerprint registering method which binarizes multivalued image data obtained by picturing an affixed fingerprint, thinning-processing a binarized image resulting from said binarizing process, extracts minutiae based on the thinning-processed image data through said thinning processing, deletes pseudo minutiae from said minutiae, and when the remaining number of minutiae is equal to or above a prescribed number, registers a fingerprint having minutiae according to said binarized image data, wherein if the fingerprint registering in said process for the first time fails, spatial filtering is effected on said multivalued image data to continue in the ridge line direction in the fingerprint registering process by said process for the second time and following, said spatial filtered multivalued image data is binarized and thinning-processed, said minutiae are extracted from said thinning-processed image data, said pseudo minutiae are deleted from said minutiae, and if the remaining number of minutiae is equal to or more than a prescribed number, the fingerprint having minutiae according to said binarized image data is registered.
 21. The fingerprint registering method according to claim 20 , wherein to delete said pseudo minutiae, when the extracted minutiae are within a prescribed area, they are judged as pseudo minutiae, and said pseudo minutiae are deleted from a list of minutiae. 